Report to the
Ministers of Agriculture and Fisheries,
Health, and Food, and to the Secretary
of State for Scotland

the Working Party on
Precautionary Measures against Toxic Chemicals
used in Agriculture


Published . .. . . . . . . . . . . . October, 1953


Appendix A :
Introduction . .......
Terms of Reference ........
Composition .........
Scope of the Inquiry .......
The Substances Used ....,..
The Search for Evidence .......
A Survey of Existing Knowledge .....
The Law for Safeguarding the Purity of the Consumer’s Food
The Part Played by Industry ......
Present Methods of Controlling the Sale and Use of Crop-
Protecting Chemicals .......
Other Hazards ........
Existing Facilities for Obtaining and Disseminating
Information about Crop-Protecting Chemicals........
Information Required for the Control of the Uses of Crop-
Protecting Chemicals ......
General Considerations...............
Summary . . ......

Crop-Protecting Chemicals
Description and Formulae ....
I     Insecticides .......
II    Fungicides ...........
III   Herbicides .......
IV   Rodenticides .......

I     Organizations which were invited to give written
      evidence to the Working Party.......
II    Organizations which provided written evidence.
III   Organizations which were invited to give oral
      evidence .......
IV   Organizations which provided oral evidence.





Report to the Ministers of Agriculture and Fisheries, Health,

and Food, and to the Secretary of State for Scotland of the

   Working Party on Precautionary Measures against Toxic

Chemicals used in Agriculture.




1. The widespread interest now shown in certain possibly dangerous effects
of the chemical treatments used to protect growing crops, livestock and stored
food is largely due to the relatively recent introduction of pest killers with
which we are less familiar than we are with the better-established poisons.
In some cases these treatments, repeated annually, provide the only known
means by which diseases, pests and weeds can be controlled. In others they
are necessary only when the weather or some other condition favours the
spread of a particular scourge. Whatever the circumstances which call for
their use, they have proved their worth in reducing waste, both in the production
and the storage of food, and it is to be expected that these treatments will
remain normal practice in many branches of agriculture and horticulture, and
that they will go on being used on an ever-increasing scale.

2. Unfortunately, almost all the insecticides and weed-killers are toxic to
forms of life other than the pests they were designed to control and, if improperly
used, they may constitute a serious hazard, not only to domestic animals and
many wild creatures, but also to man - although here the risks can sometimes
be greatly reduced by the correct timing of the treatments. The Working
Party hope that further research will disclose alternative pest-controlling
substances which will have a greater selective toxicity to insects, weeds and
fungi. Until, however, such compounds are discovered, the only way in
which the present danger can be mitigated is by efficient control of the

3. Our first report* (January, 1951) dealt with the protection of the men
who spread the new pesticides and weed—killers, and particularly with the
problem of offsetting the hazards they run when applying the more noxious
of these crop-protecting chemicals. This problem was fairly straightforward
since the dangers were obvious, and since all people engaged in the work,
from the farm worker to the spraying contractor, were equally anxious to
devise reasonable measures of protection. Legislation has now been enacted
to embody our recommendations. Our second task, that of considering the
possible hazards run by the consumer who eats food which, at an earlier stage
in its history, was treated with, or exposed to, some toxic chemical, has proved
far more difficult, and is the subject of this report.

* Toxic Chemicals In Agriculture, H.M. Stationery Office, l95l.


4. In spite of searching inquiries to as many official and unofficial bodies
as one might suppose could provide relevant information, and whom we list
later in this report, we have been unable to discover any specific instances of
illness which have resulted from eating such food. The position does not
therefore appear to have been established as one of immediate danger.

5. On the other hand, it is not one which allows of complacency. While
the present lack of any system of notification makes it impossible to find out
what proportion of the food we eat is being treated with these less familiar
chemicals, the increasing rate of introduction of new and potentially dangerous
compounds indicates that measures need to be taken to ensure that the situation
does not get out of hand, and that new materials are not used on a commercial
scale until at least a specified minimum of information is available concerning
their toxicity, and concerning the residues they leave on foods.

6. Certain of our previous recommendations were inspired by the need to
protect the public interest, as opposed to the more specific one of the people
who actually apply the chemicals. Thus we recommended that warning
notices should be placed on gates giving access to fields that are being, or have
recently been, sprayed ; that surplus spray material should be safely disposed
of to avoid any possible contamination of ponds or streams ; and that farm
animals should be kept away from spraying operations and from fields that
have recently been sprayed. We also recommended that it would be in the
interest of the retailers of chemical formulations, as well as of the public, that
the sale of preparations containing dinitro and organo-phosphorus substances
should either be brought under statutory control, or restricted. This recom-
mendation has now been implemented. In the present report we take the
problem of the risk to the consumer as far as we believe we legitimately can
on the basis of real information. In the next part of our work we propose
to consider the dangers to which animal and plant life are exposed as a
consequence of the use of various pesticides.


7. We were re-appointed jointly by the Minister of Agriculture and
Fisheries, the Minister of Health, the Minister of Food and the Secretary of
State for Scotland in May, 1951, and were given the following revised terms
of reference :

"To investigate the possible risks from the use in agriculture of toxic sub-
stances on the agricultural product and the stored product, and, if protective
measures appear desirable, to make recommendations as to their form to
the Ministers concerned."

   The terms of reference were interpreted in the press notice issued on July
19th, 1951, to mean that we were to enquire whether any risks arise, from
the point of view of the consumer of the final product, from the use of toxic
chemicals in agriculture and in the storage of food. We have assumed that
substances used for the protection of stored food include rodenticides as well
as insecticides.
We have not regarded our new terms of reference as including risks to farm
animals except in so far as these may affect the consumer of animal products.



8. The following is the composition of the Working Party during the
second stage of their inquiry :

Professor S. Zuckerman, CB., FRS
J. M. Barnes, Esq., M.B.
R. H. Barrett, Esq., M.R.C.S., L.R.C.I.,
  D.P.H., D.T.M. & ll.
A. B. Bartlett, Esq.
(from May, 1951 to September, I951)
P. N. R. Butcher, Esq., C.B.E.
W. Morley Davies, Esq.. M.A., B.Sc.,
F. A. Deny, Esq., M.Sc., M.D.
N. R. C. Dockeray, Esq.
R. A. E. Galley, Esq., Ph.D., A.R.C.S.,
D.I.C., F.R.I.C.
R. F. Giles, Esq.
(from May, 1951 to December, 1951)
C. T. Gimingham, Esq., O.B.E., B.Sc.,
W. McAuley Gracie, Esq., M.B.E.
(from September, I95I).
A. Holness, Esq., M.B.E.
P. G. Inch, Esq., O.B.E.
(from January, I95l)
B. S. Lush, Esq., M.D., M.R.C.P.
J. R. McCallum, Esq., M.C.
R. J. Peters, Esq., M.D.
H. V. Taylor, Esq., C.B.E., V.M.H., D.Sc.,
H. Cole Tinsley, Esq., M.B.E.
E. E. Turtle, Esq., M.B.E., M.Sc., Ph.D.,
F.R.I.C., A.R.C.S., D.I.C.
(from June, 1951)
H. N. White, Esq.
K. R. Allen, Esq.
(from May, l95l to August, 1951)
W. K. Melrose, Esq., B.Sc.
Mrs. E. D. Cookson
Miss D. M. M. Kenyon
Office of the Lord President of the Council
Medical Research Council
Ministry of Health
Ministry of Agriculture and Fisheries
Ministry of Health
Ministry of Agriculture and Fisheries
(National Agricultural Advisory Service)
Medical Research Council
Ministry of Food
Office of the Lord President of the Council
Ministry of Agriculture and Fisheries
Ministry of Agriculture and Fisheries (Plant
Pathology Laboratory)
Ministry of Agriculture and Fisheries
Agricultural Improvement Council
Ministry of Agriculture and Fisheries
Medical Research Council
Department of Agriculture for Scotland
Department of Health for Scotland
Agricultural Improvement Council
Agricultural Improvement Council
Ministry of Agriculture and Fisheries
Ministry of Agriculture and Fisheries
Office of the Lord President of the Council
Ministry of Food
Ministry of Food
Ministry of Food

We were assisted at our meetings with the trade and professional organ-
izations by the following, who joined us in the capacity of assessors:

Professor F. Bergel, Ph.D., D.Sc., F.R.I.C.
B. A. Ellis, Esq., M.A., F.R.I.C.
G. G. Taylor, Esq., M. Agr. Sc.
Mrs. J. Taylor, B.Sc., M.B.
Chester Beatty Research Institute
Department of the Government Chemist
Agricultural Research Council
Public Health Laboratory Service


9. We have made our inquiries under five main heads, namely :

(a) What are the substances which are being used, or which it is proposed should
    be used, to protect growing crops and stored foods?
(b) To what extent arc these compounds used, and at what stage are they added, to
    growing or stored food?


(c) To what extent is the food consumed contaminated by these materials ?
(d) What effect might such contamination have upon the consumer ?
      (In attempting to answer this question we have drawn not only on information
      collected in this country, but also on the expert knowledge of the World Health
      Organization of the United Nations and the US. Food and Drug Administration.)
(e) What are the present arrangements for controlling the use of these substances,
      and have Government Departments sufficient powers to obtain information about
      new substances before these are brought into use, and to protect the public against
      substances which, by reason of toxic residues, may be harmful to health ?

We have taken note of the facilities for research and testing which could be
provided, or which are at present available, through the Medical Research
Council, the Agricultural Research Council, the Department of Scientific and
Industrial Research, the scientific research organizations of the various
Departments, the Research Associations, the Department of the Government
Chemist, the Universities, and other organizations.


10. Apart from contamination during manufacture and processing, food
may contain the residues of chemicals applied either when it was grown or
when it was stored, or both, or which it has picked up from packaging materials
containing such protective substances.

ll. Many different kinds of toxic chemicals are used in agriculture and
on stored food. Insecticides, weed-killers and fungicides are applied to
agricultural crops, fruit and vegetables ; chemicals known as "sprout—
depressants" are applied to stored potatoes; other stored foods, such as
grain, are fumigated or sprayed or dusted with insecticides. Bacterial and
chemical preparations are used against rats which infest food stores.

12. The older toxic chemicals used to protect growing or stored crops were
in the main inorganic compounds containing lead, arsenic, or copper. The
contamination of food with these metals has been examined by the Metallic
Contamination Sub-Committee of the Food Standards Committee of the
Ministry of Food. This Committee's reports have been published, and we
decided that, since working limits have been proposed for arsenic, lead and,
in the case of a few specified foods, for copper, and since the identification
of these substances should present no problems to the analyst, it was unneces-
sary for us to discuss them further even though it might prove convenient
from the administrative point of view to consider them with the other crop-
protecting chemicals.

13. We have, therefore, given major attention to the compounds which
have been introduced in recent years, such as DDT, BHC, parathion, TEPP,
schradan, tecnazene (TCNB), propham (IPPC) and DNC. A description of
crop-protecting chemicals, with details of their chemical formulae, is contained
in Appendix A (p. 23).

14. We have also considered the dangers which may arise from the use of
chemical and bacterial rodenticides.



15. We approached 45 trade and professional organizations for evidence
about the use of toxic chemicals in agriculture and in the storage of foods;
about the risks to public health arising from the use of these substances ; and
about the residues which may remain on food at the time of sale to the con-
sumer. Lists of the organizations approached, of those which provided
written evidence, and of those which were invited to meet us in order to discuss
matters arising from their written evidence, are given in Appendix B (p. 31).
Only three organizations declined our invitation, on the grounds that they had
no information to offer.

16. The press notice issued in June, 1951, invited any firm or organization
which had information on the subject to send details to our secretariat. The
response was negligible.


17. The following survey of existing knowledge is based on evidence which
we have received directly from organizations in this country, and indirectly
from abroad, particularly from the U.S.A.

Crop-Protecting Chemicals

18. For the purpose of this inquiry, these chemicals can be considered as
falling into the following categories :
(i) Substances whose chemical or physical properties are such that significant
quantities are never likely to reach the consumer; Some of the pesticides
most dangerous to handle, e.g.,. TEPP and nicotine, fall into this group.
(ii) Substances chemically stable and physically persistent, which may remain
on crops or stored food until they are consumed. These may be grouped
under the following sub-heads:

(a) Compounds applied before the edible part of the crop has appeared, and which
      therefore do not contaminate the food itself, e.g., DNC for weed control in young
(b) Compounds removed during normal storage, processing and cooking, eg., tecnazene
     used as a potato sprout-depressant.
(c) Compounds about which sufficient is known for tolerances to be recommended,
     e.g., BHC.
(d) Compounds capable of leaving residues in food and which, as little is yet known
     about their toxicity to man or animals, constitute a possible hazard of unknown
     degree, e.g., some of the more recently introduced organo-phosphorus compounds
     and chlorinated hydrocarbons.
(e) Compounds reacting with the natural constituents of food to produce compounds
     which may be toxic, or destroying an essential factor in the food. No chemical at
     present used for crop protection is known to have the first of these properties. The
     second is manifested to a limited extent by methyl bromide when used to protect
     stored wheat.

19. Obviously there can be no sharp line of demarcation between the
groups of crop-protecting chemicals we have listed; For example, although
an appreciable amount of information about the toxicity of parathion has
been published, and routine methods of analysis developed, so that the mag-
nitude of residues in different crops can be determined, no tolerances for this


compound have yet been recommended. Parathion thus falls into group
(ii) (d) of the above classification. This group also contains some of the
newer organo-phosphorus compounds about which, as far less is known,
there is much greater concern.

20. It will be apparent that materials in group (ii) (a), such as the highly
toxic DNC and the much less toxic MCPA and 2,4-D, which are used to control
weeds in cereal crops, do not constitute a definable consumer risk. The
winter washes of fruit trees and bushes are in the same category.

21. Compounds in group (ii) (b) are not present on the food when it is
consumed, and therefore are not a potential danger to the public.

22. The compounds comprised in group (ii) (c) are believed not to con-
stitute any risk to the public if the limits laid down are adhered to. A limit
of 2.5 parts per million of the gamma—isomer has been recommended for
BHC and a tentative limit of 7 parts per million for DDT. No numerical
limit has been suggested for tecnazene and propham; the normal technique
of their application as potato sprout-depressants has been shown to yield
potatoes which contain barely detectable traces of these materials.

23. It is the chemicals of groups (ii) (d) and (e) which have caused us the
greatest concern, not because they necessarily present any greater hazard, but
because the information does not exist on which to base an estimate of the
risk they constitute.

24. Routine methods of analysis for micro—quantities of the chemicals in
or on animal and vegetable tissue are not available for all compounds. Even
when methods do exist the residues in or on foods have not always been
determined. Further, there is a lack of information concerning the decom-
position products of systemic insecticides within plants, and of their effects,
if any, on the composition of the final food. In any event, it is impossible
to conceive of animal experiments which will provide complete information
about the toxic effects of chemicals on human beings.

25. The magnitude of the risk to the consumer obviously depends on the
nature of the foods that are treated and on the intensity of the treatment.
A real danger may arise occasionally from the gross misuse of a pesticide
when applied in excessive quantities to a crop just before consumption. The
intermittent consumption of very small and undetermined quantities of toxic
chemicals constitutes a more hypothetical danger. The greatest threat of
chronic toxicity would therefore arise from the widespread treatment with
materials of group (ii) (d) and (e) of foods which form the major part of the
nation’s diet. In seeking information about this point we were immediately
faced by the difficulty that, while we might be able to discover how the food
we grow ourselves is treated, we were likely to remain incompletely informed
about the previous history of the food we import, which is still 60 per cent of
what we consume and which contains a large proportion of our staple foods.

26. Although we have not been able to obtain as much information as
we should have liked about the proportion of different home-grown crops
which receive spray treatment, such information as we have received shows
that very little of our staple foods is treated with the materials comprised in
group (ii) (d) and (e).


Treatment of Food

(a) Treatment of Food in the United Kingdom


27. Wheat seed is dressed with fungicides, and. long before the ears appear,
the young growing plant is sprayed with selective weed-killers. When the
chemicals are properly used the harvested wheat is thus free from contamina-
tion. This is still true even if spraying is delayed until some weeds, e.g.,
charlock, are in flower, although in these circumstances other hazards may
arise, for example, to honey bees. There is no evidence that the current methods
of using these chemicals in this country result in contamination of the harvested

28. Stored wheat is sometimes treated chemically to eradicate insects,
mites or rodents. Home-grown cereals generally are much less infested than
imported cereals, which are consequently the ones more frequently treated in
storage. Methyl bromide is the most usual substance employed for this
purpose. Its ability to combine with the methionine in wheat led to tests in
which heavily overdosed cereals were fed to experimental animals, without
causing harmful effects. Although further tests are being carried out, it has
already been concluded that the public runs a negligible risk in eating food
made from wheat treated in this way. It is worth noting, too, that during
the past five years the quantity of wheat treated with methyl bromide in this
country has been only about 0.5 per cent of the total consumption.


29. Maincrop potatoes are treated with preparations of copper during
growth as a protection against blight, and with other sprays to destroy the
haulms before harvesting. It has been established that the normal application
of these fungicide and haulm-destroying sprays constitutes no hazard to the

30. The longer-keeping varieties of potatoes, which have to last until the
next early crop, are given dressings with sprout-depressants when they are
clamped. The two compounds used for this purpose in Britain are tecnazene
and propham, the use of which, in the manner prescribed by the manufacturers,
is, in the opinion of the Toxicology Committee of the Medical Research
Council, free from risk to the consumer.


31. Meat and milk are not treated directly with chemicals. It has been
shown, however, that the consumption by cattle of fodder, previously sprayed
with DDT, and the spraying of cattle with this insecticide to protect them
from flies, may lead to the presence of DDT in small quantities in the body
fat and milk. Flies are far less troublesome in Britain than, for example, in
the southern states of the U.S.A. where the practice originated. Our own
cattle are therefore rarely sprayed for this purpose with persistent insecticides.

32. Fodder crops, which might be sprayed with DDT, are treated at such
times that, when consumed, chemical residues have been lost due to weathering.



33. As far as home-grown staple foods are concerned, such evidence as
there is does not therefore support the view that there is at present any danger
to the public arising from the use of crop-protecting; chemicals. Nor, as has
been said, have we been told about any case of fatal or non-fatal illness that
can be attributed to the consumption of food made from crops that have been
so treated. We wish to emphasize, however, that at the moment only rela-
tively small proportions of the total acreage; of crops are treated. For
example, chemical weed control has become normal practice with cereals,
more so perhaps than any other spraying technique, yet only 25-33 per cent
of the total acreage is sprayed. No new danger to the consumer is involved
if this particular practice extends further, provided it is carried out properly.

34. If more fodder crops are sprayed than the limited acreage now treated,
the public will continue to be immune from the risk of consuming contaminated
meat and milk, provided that adequate time intervals exist between spraying
and the feeding of the crop to the livestock.


35. The systemic and contact organo-phosphorus insecticides are mostly
used to protect the more expensive seasonal fruit and vegetable crops, such as
strawberries, blackcurrants and brussels sprouts. They are also used on hops.
We have failed to obtain detailed information about the proportions of the
total crops that are treated.

36. Our inquiries have revealed certain isolated instances in which these
spray materials, about whose toxic properties we know least, have been used
recklessly. In their instructions reputable manufacturers indicate quite clearly
both the risk to the operator applying the materials and also the time interval
which should elapse between treatment and harvesting. In some cases the
time intervals have been determined as a result of studies of the rate of dis-
appearance of the residues from the crops under ordinary climatic conditions.
Instructions based on such advice may sometimes be ignored, and it is in these
and similar circumstances, i.e., where it is impossible to say what residues are
present, that the public is exposed to an unknown risk.

37. Dangers of this kind can be completely averted only if the incorrect use
of agricultural chemicals is prevented. An essential step to the prevention of
misuse is that the official bodies should be told more about the extent of their
potential or actual use, and the conditions under which they are applied. It
is also important that no new compounds be introduced into commercial
practice until ways of offsetting the hazards they may constitute are agreed.
To do this effectively, more data are needed about the amount and persistence
of residues under different conditions, and for different crops, of some groups
of products already in use, particularly systemic and contact organo-phosphorus

(b) Treatment of Food before it is Imported

38. As already stated, we have not been able to obtain much information
about the treatment of food before it arrives in this country. Commodities
may pass through various hands before being shipped and there are obviously


practical difficulties in transmitting relevant information regarding chemical
treatments. Certain overseas producers may, in fact, not wish to disclose the
chemical treatments which their crops have received. The problem is not
simplified by the fact that in certain cases it may be very difficult, if not
impossible, to detect the presence of chemical residues.

39. However, a general picture of foreign practice in the use of agricultural
chemicals can be built up from information provided by official and commer-
cial international channels, by technical publications and from certain other


40. In most of the countries from which we import our cereals, farming
is less intensive than in the United Kingdom, and seed dressings and weed-
killers are either not used at all or are used only on a small scale. Certain
countries are, however, known to treat cereals in storage with methyl bromide
and other fumigants. At the present time this practice is very restricted, and
it could not relate to more than an exceedingly small part of our total food

41. Soon after its introduction, DDT was applied, overseas, directly to
some of the grain imported into the United Kingdom. This practice has now
been abandoned, and of many hundreds of shipments which have arrived
during the past few years, only two are known to have been treated in this way.

42. Both BHC and DDT are still occasionally used overseas in warehouses
in which cereals are stored before shipment, but, in all cases of which we
know, the procedures employed cannot be regarded as objectionable in the
light of the standards recommended by the Toxicology Committee of the
Medical Research Council in this country.


43. The more expensive seasonal fruits which are imported are likely to
be treated with compounds about which we know least, and this gives ground
for uneasiness. During 1951 it was suggested that some shipments had been
sprayed with parathion, not only during growth, but after harvesting, to
protect them during transport. However, examination of samples from these
cargoes, by tests sufficiently sensitive to detect less than one part per million
of parathion, failed to reveal its presence. These results are reassuring, but
we are aware that they do not preclude the possible arrival of particular
consignments of fruit which may have been excessively treated either during
growth or after harvesting.

General Observations on these Treatments

44. Thus we have not uncovered, in the course of our inquiry, any firm
evidence to support the view that there is at present any public danger arising
from the use of protective chemicals on our staple food. However, we need
to obtain better information about the use of pest control chemicals on foods
before reaching this country, and upon the methods of detecting the presence
of residues and measuring them at the time they are imported.



45. The infestation of food stores and warehouses by rats and mice is one
of the most serious causes of deterioration and loss of stored food, and these
animals are also carriers of disease. Their destruction is necessary on both

46. Chemical and bacterial rodenticides are used, and both constitute
potential hazards to human beings. The Agricultural Departments have
power under Section l9 of the Prevention of Damage by Pests Act, 1949, to
make regulations for controlling the methods which may be used by servicing
companies for keeping down or destroying rats and mice, including the approval
of different methods for use in different circumstances, and prohibiting the
use by servicing companies of any method which is not approved. No regu-
lations have yet been made, but the following poisons only are at present
used by the Agricultural Departments or advocated by them for general
application, namely : zinc phosphide, arsenic, antu, warfarin, and red squill.
Other chemical poisons are used in rodenticides that are sold over the counter,
and bacterial preparations are used by some contractors.

47. The dangers associated with the use of chemical rodenticides arise
essentially from the possibility that they may be accidentally consumed by
children, animal pets and farm livestock. The bacterial preparations introduce
an additional and more general risk of food poisoning, since food may become
contaminated with the bacteria which multiply rapidly under appropriate
conditions, eg., in the excreta of infected rats.

48. Because the cultures contain living organisms, there is no precise
knowledge of the numbers or virulence of bacteria present at any given time
after laying the baits. Even if the colonies die out under some conditions,
they may multiply under others. It is, therefore, much more difficult to
control the risk than when a chemical poison of known and stable composition
is used.

49. Because of this special risk, about; which disquiet has been voiced, we
have inquired into the circumstances in which these cultures are manufactured
and used as rodenticides.

50. We were particularly impressed by the following points:

(i) We were told by the firms concerned that the strains used in
     bacterial rat poisons are of the danysz variety of Salmonella
. Nevertheless, we are informed by the Public Health
     Laboratory Service that the variety jena, which is generally con-
     sidered to be more pathogenic to man, was isolated in 1949 from
     a sample of commercial rat poison.

(ii) There is no official control of the varieties of organisms employed,
     or the methods used for culturing them, for checking their virulence
     or their use under practical conditions.

(iii) Very few cases of human illness have been traced directly to the
     use of bacterial rodenticides, but the source of bacterial food-
     poisoning has been traced in only a very small proportion of all


(iv) Although most outbreaks of human illness that have been traced
     to Salmonella enteritidis have been attributed to varieties other
     than danysz, the value of this information must be assessed in
     relation to point (i), in that there is some doubt as to whether
     the variety danysz has been used exclusively.

51. The Public Health Laboratory Service and the Medical Research
     Council consider that the risks are such that the use of bacterial rodenticides
     should be discouraged with a view to their discontinuance. The Ministry of
     Agriculture’s infestation Control Division advise that immediate policy should
     concentrate on ensuring proper care and attention in the preparation and use
     of these cultures, and that any hasty action against these methods might lead
     to a serious dislocation in commercial rat-destruction services.


52. There are already on the Statute Book provisions which have the
object of ensuring that food sold to the public is free from contamination and
harmful ingredients and is tit for human consumption. These provisions are
contained in the Food and Drugs Act, 1938, and in various regulations made
under that Act. The following are relevant :

(i) it is an offence to sell for human consumption food which is unfit for that purpose ;

(ii) if food is prepared, stored or sold in a room, all reasonably necessary steps must
     be taken to prevent risk of contamination of the food ;

(iii) is an offence to add any substance to food so as to render the food injurious to
     health ;

(iv) it is an offence to sell to the prejudice of the purchaser any food which is not of
     the nature, quality or substance demanded, and if this offence arises because some
     substance has been added to the food the onus rests on the defendant to show that
     the substance is not injurious to health;

(v) it is an offence to import into England or Wales any food which has been declared
     by a competent authority in any country to be unfit for human consumption ;

(vi) an authorized officer of a local authority may seize any food which is exposed for
     sale for human consumption or which is brought into England or Wales by air,
     and if it appears to him to be unfit for human consumption he may bring it before
     a magistrate for condemnation. Similar powers may be exercised by an authorized
     officer of a Port Health Authority in respect of food imported by sea.
     The Act also confers on the Ministers of Food and Health powers to make
     regulations authorizing measures to be taken for the prevention of danger to
     health from the importation, preparation, transport, storage, exposure for
     sale, and delivery of foods of various kinds intended for sale or sold for human

53. Except as indicated below, the duty of executing and enforcing the
Act and regulations rests on the local authority, i.e., the borough or district
council. Those provisions which relate to the composition or labelling of
food are enforced by the 278 Food and Drugs Authorities in England and
Wales. Every Food and Drugs Authority is required to appoint a public
analyst to enable it to undertake prosecutions based on evidence about the
composition of food. The Public Health (Imported Food) Regulations, l937
and l948, are enforced by Port Health Authorities in the case of food imported
by sea, and by local authorities in the ease of food imported by air.


54. Authorized officers of local authorities (including Food and Drugs
Authorities) and of Port Health Authorities are given appropriate powers of
entry, inspection and sampling.

55. The position in Scotland is similar. The main statutory provisions
are Section 43 of the Public Health (Scotland) Act, 1897, which forbids the
sale or possession for sale of unsound food and enables authorized officers of
local authorities to enter premises to search for and seize unsound food ; and
Sections l and 2 of the Food and Drugs (Adulteration) Act, l928, which
corresponds to provisions in the 1938 Act referred to above. The Scottish
Imported Food Regulations are similar to the English. All food statutes and
regulations are enforced by corresponding authorities, i.e., 55 county and large
borough councils.


56. While it is reassuring that we have found no evidence of danger arising
from the eating of food made from crops that have been treated with chemicals,
we fully appreciate that risks may exist even if they cannot be given scientific
definition, and that steps should be taken to prevent a disquieting situation
from getting out of hand.

57. We have been assured by the larger manufacturers of agricultural
chemicals and the firms that apply them that they are aware of the risks attached
to the use of the materials, and that they are anxious to co-operate in their
reduction. A few manufacturers have facilities for investigating the toxic
properties of, and analytical procedures for, the compounds they make or sell.
While all do their best to disseminate information about the correct use of
their materials, they can do little to ensure that their recommendations are

58. The food manufacturers pointed out that they have no way of finding
out what chemicals had been used on the food they receive as raw materials.
They thought any attempt to get this information from the primary producers
was unlikely to be successful, and would only increase the existing difficulties
of obtaining raw materials. They do, however, carry out many analyses for
materials, such as arsenic, for which limits have been recommended, but it
does not seem practical to ask these firms to examine all their products for the
suspected presence of a range of compounds, each requiring a special analytical
method. Their co-operation could be expected for any reasonable requirements
such as the setting up of a permitted limit for a new pesticide.

59. We have been assured by all the responsible organizations who provided
us with evidence that they are prepared to co-operate in any reasonable measures
which might be introduced in order to prevent the hazards we are discussing
from materializing.


60. A voluntary "Crop Protection Products Approval Scheme" has been
operated by the Agricultural Departments since 1942. The main object of
the scheme is to give guidance to the grower in the purchase of crop-protecting


chemicals. Products are approved which comply with standards of compo-
sition and performance prescribed by these Departments for the purpose
given on the labels of the containers.

61. Thus both the labels and the products are approved. As it is impossible
to arrive at a standard of performance of new compounds except after trials
lasting about three seasons, the scheme does not normally apply to the most
recently-introduced compounds.

62. The scheme is voluntary, and a firm is not bound to submit a new
product or a new formulation of an old one for approval before it is marketed.
There is, therefore, no official control of new materials, and any manufacturer
who is reluctant to disclose the nature of his product can market any product
he likes for use on the growing crop, and give whatever instructions he wishes
for its use.

63. The voluntary Approval Scheme does not apply to rodenticides or to
insecticides and fungicides for use against pests in domestic or industrial
premises during the storage of foodstuffs. A compulsory licensing scheme to
cover such products was operated by the Ministry of Food, and later by the
Agricultural Departments, from 1945 to 1950. When the Prevention of
Damage by Pests Act of 1949 came into force powers of licensing were dropped
and the retail trade was freed. However, the Agricultural Departments still
have power to control by regulations the methods used by commercial servicing
companies who destroy pests, although these powers have not yet been used.

64. There is no voluntary scheme for domestic insecticide and rodenticide
preparations, nor is there any official control of the products sold, or of their
method of use.

65. New administrative precautions are required if a reasonable check on
the introduction of new toxic compounds is to be maintained, so that only
those about which sufficient toxicological and analytical data are available
could enter the market. In view of the industry’s willingness to co-operate
in any reasonable measures to prevent danger to the public, it should be
relatively simple to arrive at a satisfactory solution to this problem.


66. We have dealt so far with the risks that may arise from the ingestion
of chemical residues on food. The public, however, may be subjected to
certain additional hazards. Although the Pharmacy and Poisons Act, I933,
prohibits the general sale to the public of the more toxic chemicals used for
such purposes as pest control, carelessness in the storage and handling of
pesticides either in food stores, restaurants or private homes has been a cause
of accidents.

67. Under certain conditions, the use of insecticide vapourizers could, for
example, result in food becoming contaminated.

68. The handling of growing plants or stored products treated with toxic
chemicals may also be a possible source of danger. Thus workers who remove
leaves to aid ventilation in hop-gardens may be harmed by the toxic sap which
is exuded during this operation from plants which have been treated with
systemic insecticides.


69. Of the other situations which can be envisaged, where collateral hazards
of a specific nature might arise, it would appear that they are dealt with either
by appropriate legislation or arrangements made to meet the specific situation.
Thus transport regulations control the packaging and labelling of dangerous
chemicals so that risks are minimized. Materials which might render food
unpalatable have to be clearly marked, so that they are kept far apart from
foodstuffs and empty foodstuffs containers. The laundering of the clothes
worn by men who use certain toxic sprays in the field might also constitute
a risk, but contractors have already attempted to deal with this problem on
their own or by making special arrangements with local laundries.


70. The following facilities exist in this country for obtaining information
about the toxicity of chemicals used in agriculture, about residues arising
from their use and about analytical methods.

A. Government Departments and Research Councils

(i) Agricultural Departments

The Departments are responsible for the preservation of Government stocks
of stored products from attack by rodents, insects or mites, and for giving
advice to public authorities and to industry, and for enforcement where neces-
sary under the Prevention of Damage by Pests Act, 1949. They develop new
techniques for rodent and insect control and work closely with the Pest Infest-
ation Laboratory of the Department of Scientific and Industrial Research.
The Departments are also concerned with problems involving the toxicity of
agricultural chemicals, and the Plant Pathology Laboratory undertakes the
secretarial duties in connection with the approval of pesticides for use in
agriculture under the Crop Protection Products Approval Scheme. The
agricultural advisory services of the Departments collaborate in the later stages
of the development of new measures for crop protection and advise farmers
generally on their use.

(ii) Ministry of Food

THE SCIENTIFIC ADVISER'S DIVISION co-ordinates information about the effect
on food of the addition of chemicals during processing and manufacture, and
of chemicals which appear adventitiously as residues in food.

(iii) Department of Scientific and Industrial Research

THE PEST INFESTATION LABORATORY is primarily concerned with research into
the infestation of stored foodstuffs both in the United Kingdom and in the
Colonies. Its interests include the assessment of the value of fumigants and
contact insecticides for the prevention and control of insect attack in food-
stuffs; the elaboration of methods of application; the design of suitable
chemicals and biological methods of assay ; the determination of the residues
likely to be found in various products ; and the study of the way the chemicals
affect insects.


THE DITTON LABORATORY. This institution is concerned with the preserva-
tion of fruit and vegetables, and also with the efficiency of pesticides and the
possible risks involved.

(iv) The Agricultural Research Council

Units of the Agricultural Research Council deal with specific aspects of crop
protection. Thus the Unit of Insect Physiology embraces in its investigation
the penetration and mode of action of insecticides, and the Unit of Experi-
mental Agronomy includes in its programme fundamental studies and field
experiments on selective weed-killers.
    The Council also finances fundamental research in University Departments.
The Fungicide and Insecticide Research Co-ordination Service is an inter-
departmental organization which co-ordinates research and development
activities in the agricultural, as well as in the industrial and medical fields.

(v) Grant-Aided Agricultural Research Institutes

These institutes, which include such Research Stations as Rothamsted, East
Malling and Long Ashton, cover different branches of agriculture and horti-
culture. Most are concerned with the pests and diseases of one or more crops
and with their control by chemical means.

(vi) The Medical Research Council

Two units formed by the Council carry out research work in the field of toxic
chemicals :

(a) THE TOXICOLOGY RESEARCH UNIT was formed to assist in the solu-
     tion of toxicological problems and to pursue research in fundamental
     questions arising from the problems referred to it. It has been con-
     cerned with the mode of action of toxic agents, and with the design
     of tests rather than with the carrying out of routine examinations.

     its other interests, is concerned with cases of poisoning that have
     occurred in factories and amongst agricultural workers. It is inter-
     ested in the general problem of the use of agricultural chemicals.

The Toxicology Committee is a standing advisory committee appointed by
the Medical Research Council to advise it on research in problems in toxicology.
On occasions the advice of this independent committee on toxicity problems
has been sought by Government Departments, industrial firms and private

B. Industrial Research Associations

     The British Baking Industries Research Association, the British Food
Manufacturing Industries Research Association and the Research Association
of British Flour Millers, which are jointly financed by the Department of
Scientific and Industrial Research and the respective industries, possess certain
information about the treatment of the commodities with which they are

C. Industry

     The larger organizations have their own research and analytical laboratories.
A few carry out toxicological investigations, although this is done much less
frequently and on a smaller scale than in the U.S.A. We have been told, by


representatives of the chemical manufacturers, of analytical methods evolved
for the detection of toxic residues on crops, of analytical data on residues,
and of toxicity tests. Numbers of the smaller firms, however, had no such
data to present, and apparently do not have the laboratory facilities to obtain
them. Some firms have analytical work and biological assays done for them
by industrial consultants.
     The practice of seeking advice from the personnel of University Depart-
ments by industrial firms is apparently extensive, but we have no knowledge
of its precise magnitude.

D. University Departments

     University Departments have made valuable contributions to the study of
the newer pesticides. Much of the work has been financed by Government
funds. In some cases an extramural contract has been given by a Government
Department to a University Department to carry out an agreed piece of
research ; in others, workers have been seconded from Research Councils to
University Departments ; in others, again, funds have been provided to support
investigators working on special problems. The results of such work are
published as scientific papers, or communicated to the appropriate organization
by written report.


71. Three things are needed if measures designed to control the use of
toxic substances in agriculture are to be effective from the point of view of
the consumer :

(i) A knowledge of the nature and extent of the use of all toxic substances in agriculture
     and in food storage.
(ii) Methods of analysis which allow the extent of any food contamination to be
(iii) Adequate information about the toxic properties of the materials as they affect
     mammals so as to allow a reasonable assessment to be made of the human risk.

72. These needs would be adequately met if the following conditions were
to obtain :

(i) A firm proposing to sell a new chemical which might contaminate food when used
     for its advertised purpose, would be responsible for providing adequate information
     under all the heads listed in paragraph 71 above before offering the material for sale.
(ii) The Government Departments concerned would satisfy themselves that the public
     would be adequately protected from any potential risk that might arise from the
     use of the proposed new material. The Government Department could be advised
     by a committee such as that suggested in paragraph 76.

73. The existing situation falls short of this ideal in the following respects :

(i) Many of the firms producing these materials do not have adequate facilities for
     obtaining the necessary toxicological data about the materials they produce. Nor
     are there research laboratories which they can pay to do this work for them.
(ii) Compounds can be marketed and used on food crops without any reference to
     official bodies.
(iii) Government Departments have no means of obtaining adequate information about
     the introduction of new preparations except by the goodwill of the firm concerned.
     They cannot, therefore, be expected to have a complete knowledge of new compounds
     and the extent to which they are used.
(iv) Precise information about the way a given shipment of imported food has been
     treated before purchase is often unavailable. Even if the organization were avail-
     able to attempt the formidable task of undertaking analyses of imported food
     cargoes, it would not be possible to obtain a complete check owing to the difficulties
     in sampling, and, in some cases, to the absence of chemical methods of detection.



74. British Health authorities, and Government Departments concerned
are not grappling in isolation with the questions discussed in this report.
Other countries, and particularly the United States of America, where con-
siderable attention has been devoted to the matter. have experienced precisely
the same difficulties as we have in attempting to control the ever-increasing
number of new chemicals that are being introduced into agricultural and
horticultural practice. There is common agreement that it would be as
unreasonable to advocate the general suppression of the newer methods of
crop protection because of the possible, but undefined, hazards they entail,
as it would be to deny the existence of a problem and the need for measures
by which it could be minimized.

75. The nature of the problem is plain enough, The elimination of agri-
cultural waste has become the prime purpose of a young and vigorous industry,
and we are now faced by a growing number of pest- and weed—killers which
increase the efficiency of food production, but whose collateral toxic effects
are in general insufficiently known. Public fears about the dangers of chronic
illness from eating possibly contaminated food are hardly going to be allayed
by statements that there have been no fatal accidents so far, or that chronic
illness is not to be expected because none was observed in experimental rats
which over a year or so ate food that had been dosed with the new chemicals
used in crop protection. Disquiet will give way to confidence only if the
public is satisfied that a constant watch is being kept over the problem, and
that every reasonable precaution is being taken to obviate possible risks.

76. While several official bodies, referred to in paragraph 70, are already
concerned with different aspects of the whole problem, it is our view that
some central body is needed whose main function would be to direct or
co-ordinate the collection of information about the use of toxic substances in
the protection of growing crops and stored food, and to advise the Ministers
concerned about administrative measures which may be required to obviate
such risks to the eventual consumer as may arise from the use of such sub-
stances. It is unnecessary for us to specify the precise constitution of such a
central body, but we suggest that, if it consisted of an administrative and tech-
nical representative from each of the Departments concerned, it would be able
to maintain the necessary links with those separate agencies which are dealing
in a specialized way with different aspects of the whole problem.

77. We also suggest that the Committee should have an independent
Chairman, and that, since it would be composed of members with other
important duties, it would need a permanent secretariat.

78. This central committee would satisfy itself that the appropriate depart-
mental organizations collected all the information about the effects of the
various chemicals used to protect crops and stored food, and would have the
responsibility of passing the information, together with advice about desirable
measures, to the other Departments concerned. It would also be available
to Departments for consultation about any new chemicals that industry pro-
posed to introduce. Here its decisions would have to be based on reasonable
assessments of possible risks, since they will undoubtedly have to be made


on an amount of evidence far short of the ideal. In addition, the central
committee should be charged with the responsibility of finding the most
reasonable ways, possibly through the World Health and the Food and Agri-
culture Organizations of the United Nations, for devising an international
code of practice designed to minimize risks to the consumer arising from the
use of chemicals in the protection of growing and harvested crops. Such an
arrangement would have distinct advantages for a country such as ours which
imports more than half its food. At the present moment there are no inter-
nationally accepted limits for the contamination by crop-protecting chemicals
of commodities going into international trade.

79. As we have already indicated, we have not been given any conclusive
evidence that the public has ever suffered harm as a result of crop-protecting
chemicals — in spite of the number of different possible ways that a hazard to
the public could arise. The existence of such a central body charged with the
responsibilities we have outlined would help to guard against any deterioration
in the present situation. But, to be effective in the administrative field, it
would need to call on much more information than exists at the moment.

80. It is obvious that the whole area of ignorance about crop-protecting
chemicals — whether in the laboratory or in the public mind - must be decreased.
We need better administrative measures than exist to find out what current
practice is so as to decrease the possibility of the misuse of dangerous chemicals.
We need better and easier analytical methods of detecting chemical residues on
food. And we need to spread knowledge about these methods and about
the risks to which residues might give rise. Industry will do all it can to
discover chemicals that will control plant diseases and pests, but which at the
same time are not toxic to man and his domestic animals. Until such chem-
icals are discovered, it is essential that all new crop-protecting chemicals
should be scrutinized before being introduced commercially. This should be
done by the Departments concerned in consultation, where necessary, with
the central committee we have suggested, and manufacturers should be pre-
pared to submit full information about the nature of any new preparations
and about such tests as they have undertaken to discover what collateral risks
of poisoning, if any, they might entail.

81. We do not wish to suggest that any burden should be imposed, either
upon industry or on Government Departments, which cannot be discharged.
We do not, for example, believe that the food manufacturer could be expected
to test all food he received for all possible toxic residues.


82. We have arrived at the following conclusions :

(i) Efficient agricultural practice necessitates the use of various chemicals in
order to protect growing and harvested crops. Most of these chemicals are
toxic to more than the particular scourge they are designed to check, and
practically all of them are poisonous to man and domestic and wild animals.
We have considered the human risk that might arise from the presence of
toxic chemical residues in food entering the market, and have approached
45 trade and professional organizations for information about the risks to
public health that derive from residues on food. We have not received any
evidence of fatal or non—fatal illness that can be attributed to this cause.


(ii) Special attention must be paid to possible risks of staple articles of diet
being contaminated through treatment with chemicals.

(iii) Toxic materials have occasionally been improperly used, and small quan-
tities may find their way into food. This indicated the need for closely super-
vising the use of these chemicals.

(iv) Only 40 per cent of our food is grown at home and only a fraction of this
is ever treated by toxic chemicals at any stage. Of the 60 per cent that is
imported little is known of the methods of treatment or of the chemicals used.

(v) Bacterial rodenticides may create special risks of food contamination.

(vi) The Food and Drugs Act, l938, and (in Scotland) the Food and Drugs
(Adulteration) Act, l928, already prohibit the sale of food to which any
substance has been added which renders the food injurious to health. It is,
therefore, in the manufacturers own interests to comply with any methods
of control which would ensure that foods are free from toxic materials.

(vii) Many manufacturers of crop-protecting chemicals already take some
precautions to assure themselves that if their instructions are followed no
risk from residues attends the use of the substances they market. Most
contractors who use the chemicals are also concerned to follow a strict code
of practice.

(viii) In spite of (vii) the evidence suggests that there are compounds in com
mercial use about whose residues on food little is known.

(ix) The authorities responsible for enforcing the Food and Drugs Act and
the regulations made under it should be advised about the crops on which
the newer crop-protecting chemicals may have been used and about methods
of analysis for detecting contamination.

(x) There is a general lack of information about the use of crop-protecting
chemicals. The situation could be improved by augmenting the existing
facilities for obtaining such information.


83. We recommend :

(i) That an Advisory Committee be appointed by the appropriate Departments
with the following general functions

(a) To advise Departments on problems relating to the risks to the consumer arising
     from the use of toxic substances on agricultural products and in the storage of food.

(b) To guide Departments as to the scope of the initial investigations which should
     be undertaken by manufacturers and about the evidence which should accompany
     proposals to introduce new substances.

(c) To maintain close contact with such other official and unofficial agencies as may
     be concerned in different aspects of the problem, so as to be closely informed as
     possible about hazards.

(d) To advise Departments where necessary about the maximum permissible limits
     for residues arising from the use of toxic substances on agricultural products and
     in the storage of food.

The Committee should be provided with such staff as will permit it to
discharge its duties.


(ii) That a general statement should be issued by Departments That proposals
by manufacturers and distributors for the use of new toxic substances on
agricultural products, or for new users of those already in use should he notified
to them. Manufacturers and importers should agree that new chemicals or
new formulations would not be introduced into practice until cleared with the
Departments concerned, if necessary on the advice of the Committee referred
to in (i) above. Manufacturers and importers should therefore be prepared
to submit full information about the constitution of preparations ; about
methods available for determining the extent of any contamination ; about
the toxic properties of residues in relation to risks to human beings; about
tests carried out to establish levels of toxicity, and also any other information
which might be asked for by the Departments concerned. These arrangements
should also apply to any chemicals at present in use about which information
is thought to be inadequate. Labelling should also be agreed with the Depart-
ments concerned to see that correct instructions about the use of the preparations
are clearly stated.

(iii) That general enabling powers should be sought, as soon as opportunity
offers, for use if further experience shows that the making of statutory regu-
lations is necessary to ensure that arrangements on the lines proposed in (ii)
above work effectively.

(iv) That the advisory services of the Agricultural Departments should closely
follow the use of these materials and, by advice and guidance to users, should
ensure that as far as possible compounds are used correctly for treating the
appropriate diseases or pests.

(v) That further studies be made of the desirability of registering all firms or
individuals who apply these materials by contract, or of farmers who undertake
to provide a similar service to other farmers, so as to ensure that they are
sufficiently aware of the proper techniques and times of application of the
materials they handle.

(vi) That research should be encouraged with the objects of :

(a) developing substances effective in destroying weeds, fungi, insects and other pests,
     but which are less toxic to man than those in current use, or which do not persist
     and remain in the food he consumes ;

(b) determining the toxic properties of any substances appearing in food as a result
     of the use of crop-protecting chemicals.

(vii) That, as analytical control will be necessary, if permitted limits are
instituted, the Department of the Government Chemist and other appropriate
Departments, in collaboration with the Society of Public Analysts and Other
Analytical Chemists, should be invited to seek methods of determining micro-
quantities of toxic substances in food, which could be used in Public Analysts

(viii) That the firms and Departments concerned should give consideration to
the expert view that because of possible risks to the public health, it is desirable
to avoid the use of bacterial rodenticides. Time should be allowed for any
change-over to other methods not involving the same risks, so as to avoid
serious interference with rat destruction work. So long as they are in use
bacterial rodenticides should only be manufactured and used subject to the
following safeguards :


(a) Bacterial rodenticides should he limited to those containing the danysz variety alone
     of Salmonella enteritidis.

(b) The use of bacterial rodenticides should not be permitted in kitchens or other
     premises in which food is prepared or sold.

(c) Bacterial rodenticides should be used only by skilled operators employed by recognized

(d) Unconsumed baits containing bacterial cultures should be removed.

(ix) That international action should be encouraged with the aim of controlling
the use 0f certain chemical treatment of food going into international trade and
of promoting the exchange of information.


Signed on behalf of the Working Party,



April, 1953.




Description and Formulae

     Materials listed below have been grouped as follows : I. Insecticides,
II. Fungicides, III. Herbicides, and IV. Rodenticides. All the chemicals
mentioned are in commercial use but some of the new materials are at present
used only on a restricted scale.

     Column 1. The accepted common name (British Standard 1831 : Part I:
1952) is given. Where a common name does not exist, the code letters used
by the commercial firm concerned with development of the chemical are used
as a reference.

     Column 2. The chemical name given is the one most generally accepted
although alternative names are sometimes used.

     Column 3. Brief references are given to the categories of commodities on
which the chemicals are employed. The following classification has been
adopted :

Stored products include crops which may be treated after harvest for prevention or
eradication of insect pests during storage or in transit.
Growing plants include all stages of crops which may be treated up to harvest.
Livestock refers to sheep and cattle treated with insecticides for control of external
parasites and other pests such as flies and mosquitoes.
Seed is a special group in which chemicals are used to control pests and diseases by
treating the seed from which a crop will later be grown.
Soil is included to indicate those chemicals applied to the soil for prevention of disease
or pests on growing plants.
Ground baits form a special group of chemicals applied to the surface of the soil to
attract and kill pests which would otherwise attack the adjacent crops.

     It should be noted that this classification serves only to indicate the type of
commodity treated and does not mean that any one chemical is used on all
commodities in a given classification. Thus although DDT is used on some
growing plants the great majority of crops are not treated.
     In column 3 an indication is also given as to whether the compound is used
in the United Kingdom (U.K.) or whether it is at present used only overseas.

     Column 4. Gives information on the persistence and site of action of the
chemicals only as insecticides, fungicides, or herbicides and does not in any
way indicate their action towards man. The following terms are employed :

Persistent. Compound persists unchanged or in a changed but active form for several
months unless removed by weathering or other mechanical means or by chemical
Semi-persistent. Compound commences to break down chemically to inactive com-
pounds immediately or is lost by volatilization but active residues still persist for one
to several weeks.
Non-persistent. Compound breaks down chemically or is lost by volatilization within
a few days.
Surface contact. Chemical acts by contact. The chemical may be applied direct to
the insect, fungus or plant or may provide a protective cover on the plant, seed or animal
with which the insect or fungus later comes in contact.
Stomach poison. The chemical is ingested by the insect and acts through the gut.
Fumigant. The chemical is sufficiently volatile to form a toxic vapour and enter the
insect or fungus in this state.
Systemic. The chemical enters the plant tissue and is distributed through the plant.
Compounds distributed through the plant are toxic to insects, or inhibit plant growth.
Sprout-depressant. A chemical applied to stored potatoes to retard germination.



Common Name
Code Number
Chemical Name
Type of
and Site of
A.Halogenated Hydrocarbon Compounds
Benzene hexachloride
Gamma-isomer of the above,
A complex chemical
mixture,in which
pp'-DDT predominates.
1 : 1 : 1-trichloro-2 : 2-di-
(p-chlorophenyl) ethane.
1 : 1-bis (p-chlorophenyl)
2 : 2-dichloroethane.
1 : 1 : 1—trichloro-2 : 2-di-
(4·methoxyphenyl) ethane.
Contains not less than
85% of 1 : 2 : 3 : 4 : 10 : 10-
hexachloro-6 : 7-epoxy-
1 : 4: 4a : 5 : 6 : 7 : 8 : 8a-
octahydro-1 : 4 : 5 : 8-
dimethanonaphthalene and
not more than 15% of
insecticidally active related
Contains not less than
95% of 1 : 2 : 3 : 4 : 10 : 10-
hexachloro-1 : 4 : 4a : 5 : 8 : 8a-
hexahydro-1 : 4 : 5 : 8-di-
methanonaphthalene and not
more than 5% of
insecticidally active
related compounds.
Chlorinatcd camphene
(67-69% chlorine).
2 : 3 : 4 : 5 : 6 : 7 : 10 : 10-
octachloro-4 1 7 : 8 1 9-
tetrahydro—4 : 7-
benzene sulphonate.
Carbon tetrachloride
Stored products ;
growing plants ;
livestock ; seeds ;
soil ; ground baits ;
U.K.and overseas.
Stored products ;
growing plants :
livestock ; soil ;
U.K. and overseas.
Growing plants ;
livestock ; overseas.
Growing plants ;
soil; overseas.
Growing plants ;
soil ; ground baits ;
Growing plants ;
livestock ; ground
baits ; U.K. and
Growing plants; ,,
ground baits ;
livestock ; soil ;
Growing plants ;
Growing plants ;
Growing plants ;
Stored products ;
soil ; U.K. and
Persistent ;
surface contact ;
stomach poison ;
Persistent ;
surface contact ;
stomach poison.
Persistent ;
surface contact ;
stomach poison.
Persistent ;
surface contact ;
stomach poison.
Persistent ;
surface contact.
Persistent ;
surface contact.
Non-persistent ;


Common Name
Code Number
Chemical Name
Type of
and Site of
Methyl bromide
Methyl bromide
Ethylene dibromide
Ethylene dichloride
1 : 2-dichloropropane,
1 : 3-dichloropropylene
in approximately equal
Methylallyl chloride.
Dichloroethyl ether.
Stored products ;
soil; U.K, and
Growing plants ;
Soil ; U.K. and
Stored products ;
Stored products ;
Stored products ;
soil; U.K. and
Stored products ;
Non-persistent ;
B. Organo-phosphorus Compounds
Tetraethyl pyrophosphate.
OO-diethyl 0-p-nitrophenyl
acid ester of 7-hydroxy-
0 : O-dimethyl dithio-
phosphate of dicthyl—
[formerly known as
S- (1 : 2-dicarbethoxyethyl)
0 : 0-dimethyldithiophosphate].
anhydride or Octamethyl-
fluorophosphine oxide.
fluorophosphine oxide.  
Growing plants ;
U.K. and overseas.
Growing plants ;
soil ; U.K. and
Growing plants ;
Growing plants ;
Growing plants ;
U.K. and overseas.
Non-persistent ;
surface contact.
Semi-persistent ;
surface contact ;
stomach poison.
Semi-persistent ;
stomach poison ;
Semi-persistent ;
surface contact ;
stomach poison.
Semi-persistent ;
surface contact.
Semi-persistent ;


Common Name
Code Number
Chemical Name
Type of
and Site of
ester of b-ethyl mercapto-
0·ethyl o-p-nitro-phenyl
benzene thiophosphate.
Growing plants ;
Semi-persistent ;
Semi-persistent ;
surface contact ;
stomach poison.
C. Nitrophenol Compounds
2-methyl-4 : 6-
4 : 6-dinitrophenol or
2-sec-butyl—4 : 6-dinitro-
phenol, or 2 : 4-dinitro-6-sec-
Dormant trees ;
U.K. and overseas.
Dormant trees ;
U.K. and overseas.
Semi-persistent ;
surface contact.
Semi-persistent ;
surface contact.
D. Compounds of Vegetable Origin
Mixture of Pyrethrins I and II
and Cinerins I and II
extracted from
pyrethrum flowers.
Mixture of rotenone and
related compounds extracted
from roots of Derris, Loncho-
carpus, and Tephrosia spp.
Stored products ;
growing plants ;
U.K. and overseas.
Stored products ;
growing plants ;
livestock ; U.K.
and overseas.
Growing plants ;
livestock ; U.K.
and overseas.
Nonpersistent ;
surface contact ;
stomach poison ;
Semi-persistent ;
surface contact.
Semi-persistent ;
surface contact ;
stomach poison.
E. Inorganic Compounds
Lead arsenate
Basic lead
Paris green
Diplumbic hydrogen arsenate.
Mixture of ill-defined
basic arsenates.
Calcium arsenate.
Copper aceto-arsenite.
Sodium fluorosilicate.
Sodium fluoroaluminate.
Barium fluorosilicate.
Mercurous chloride.
Growing plants ;
soil ; U.K. and
Soil ; ground baits ;
U.K. and overseas.
Growing plants ;
ground baits ; U.K.
and overseas.
Soil ; Seed ; U.K.
and overseas.
Persistent ;
stomach poison.


Common Name
Code Number
Chemical Name
Type of
and Site of
F. Miscellaneous Compounds
Prussic acid
Calcium cyanide
Ethylene oxide
Tar oil
Petroleum oil
Petroleum oil
Carbon disulphide.
Hydrogen cyanide.
Calcium cyanide.
Ethylene oxide.
1-one ester of a
mixture of cis-and trans-
di-chrysanthemum mono-
carboxylic acid.
(3 : 4-methylene dioxy-
6-propyl benzyl) (butyl)
diethylene glycol ether.
Phenolic compounds,
obtained from coal-tar
Highly-refined light
petroleum oil.
Partially-refined heavy
petroleum oil.
Stored products ;
soil ; U.K. and
Stored products ;
soil; growing
plants ; U.K. and
Stored products ;
U.K. and overseas.
Growing plants ;
U.K. and overseas.
Stored products ;
livestock ; overseas.
Synergist for
pyrethins ; U.K.
and overseas.
Dormant trees ;
U.K. and overseas.
Growing plants ;
U.K. and overseas.
Dormant trees ;
U.K. and overseas.
Semi-persistent ;
Semi·persistent ;
surface contact.
Semi-persistent ;
surface contact.
Persistent ;
surface contact.



Common Name
Code Number
Chemical Name
Type of
and Site of
A. Inorganic Compounds
Lime sulphur
Chemical combination of
copper sulphate and lime.
Chemical combination of
copper sulphate and
sodium carbonate in water.
Various compounds such as
copper oxychloride,
copper carbonate and
copper oxide.
Elemental sulphur in
various physical forms.
Mixture containing
calcium polysulphides.
Mercuric chloride.
Mercurous chloride.
Growing plants ;
U.K. and overseas.
Growing plants ;
seeds ; U.K. and
Growing plants ;
soils ; U.K. and
Seed ; U.K. and
B. Dithiocarbamate Compounds
Ferric dimethyl-
Zinc dimethyldithio-
Disodium ethylenebis-
Zinc ethylenebis-
Growing plants ;
U.K. and overseas.
Semi-persistent ;
C. Organo-mercury Compounds
Aromatic mer-
cury compounds
Phenyl mercuric chloride.
Phenyl mercuric acetate.
Various compounds such as
ethyl mercuric chloride,
iodide and phosphate.
Various complex compounds
such as hydroxy mercuric
Growing plants ;
U.K. and overseas.
Seed ; U.K. and
Seed ; U.K. and
Persistent ;
Persistent ;


Common Name
Code Number
Chemical Name
Type of
and Site of
D. Miscellaneous Organic Compounds
Tetrachloro nitrobenzene.
N-trichloromethyl thio
tetrahydro phthalimide.
Heptadecyl glyoxalidine.
Tetra chloro-p-benzo-
2 : 3-dichloro, l-4-naph-
Growing plants ;
soil ; seed ; U.K.
and overseas.
Seed (potatoes) ;
U.K. and overseas.
Growing plants ;
U.K. and overseas.
Growing plants ;
Growing plants ;
seed ; overseas.
Soils; U.K. and
Semi-persistent ;
Persistent ;
surface contact.


Common Name
Code Number
Chemical Name
Type of
and Site of
A. Inorganic Compounds
Sodium chlorate
Oil of vitriol
Sodium chlorate.
Sodium arsenite.
Sulphuric acid.
Growing plants ;
U.K. and overseas.
Semi-persistent ;
Persistent ;
Non-persistent ;
B. Organic Compounds
2 : 4-dich1orophenoxy-
acetic acid.
2 : 4 : 5-trichlorophenoxy-
acetic acid.
acetic acid.
Isopropyl N-phenyl-
Growing plants ;
U.K. and overseas.
Persistent ;
contact (Sprout-


Common Name
Code Number
Chemical Name
Type of
and Site of
Proxan (Sodium)
Tar acids
Petroleum oils
Sodium isopropyl xanthate.
Sodium trichloroacetate.
2—methyl-4 : 6-dinitrophenol.
4 : 6-dinitrophenol or 2-sec-
butyl-4 : 6-dinitrophenol, or
2 : 4-dinitro-6-sec-butyl-
2 : 4-dinitro-6-cyclohexyl-
2 : (l-methyl-n-butyl)-4 : 6-
Phenolic compounds
obtained from coal-tar
Distillates high in unsaturated
Growing plants ;
U.K. and overseas
semi-persistent ;
Persistent ;
contact; systemic.
Semi-persistent ;
Semi-persistent ;


Common Name
Chemical Name
Zinc phosphide
Barium carbonate
Thallium sulphate
Red squill powder
Bacterial preparations                   
Zinc phosphide.
Barium carbonate.
Thallium sulphate.
Arsenious oxide.
Alpha-naphthyl thiourea.
Red squill powder.
Based on cultures of Salmonella                  
enreritidis, variety danysz.




I. Organizations which were invited to give written
evidence to the Working Party

The Research Association of British Flour Millers.
The British Food Manufacturing Industries Research Association.
The Fruit and Vegetable Canners’ Association Research Station.
The British Baking Industries Research Association.
The Cake and Biscuit Alliance Ltd.
The Cocoa, Chocolate and Confectionery Alliance Ltd.
The Food Manufacturers' Federation Incorporated.
The National Dried Fruit Dealers' (War Emergency) Federation.
The National Federation of Fruit and Potato Trades Ltd.
The Joint Council of British Potato and Vegetables Merchants' Associations.
The Scottish Potato Trade Executive.
The Scottish Seed and Nursery Trades Association.
The Horticultural Trades Association.
The British Agricultural Contractors’ Association.
The National Federation of Corn Trade Associations.
The National Association of British and Irish Millers Ltd.
The Scottish Oatmeal Millers' Association.
The British Pearl Barley Millers' Association.
The Brewers' Society.
The Maltsters’ Association of Great Britain.
The Scotch Whisky Association.
The Hops Marketing Board.
The National Union of Agricultural Workers.
The National Farmers' Union.
The Ulster Farmers' Union.
The National Farmers' Union of Scotland.
The Trades Union Congress.
The Co·operative Union Ltd. (Parliamentary Committee).
The Society of Public Analysts and Other Analytical Chemists.
The Association of Public Analysts of Scotland.
The Royal Institute of Chemistry.
The Chemical Society.
The Society of Chemical Industry.
The Royal Sanitary Institute.
The Pasteur Institute.
The National Committee of Port Public Warehouse Keepers' Associations.
The Association of Sea and Air Port Health Authorities.
The Association of Industrial Medical Officers.
The British Medical Association.
The Medical Practitioners' Union.
The Society of Medical Officers of Health.
The Ministry of Labour and National Service (Factory Inspectorate).
The Association of British Insecticide Manufacturers.
The Association of British Chemical Manufacturers.
The Industrial Pest Control Association.

II Organizations which provided written evidence

The Research Association of British Flour Millers.
The British Baking Industries Research Association.
The Cocoa, Chocolate and Confectionery Alliance Ltd.
The Food Manufacturers' Federation Incorporated.
The National Dried Fruit Dealers (War Emergency) Federation.
The National Federation of Fruit and Potato Trades Ltd.
The Scottish Potato Trade Executive.
The National Union of Agricultural Workers.
The Scottish Oatmeal Millers' Association.
The British Pearl Barley Millers` Association.
The Brewers' Society.
The Maltsters' Association of Great Britain.
The Scotch Whisky Association.
The Hops Marketing Board.


The National Farmers' Union.
The Co-operative Union Ltd. (Parliamentary Committee).
The Pasteur Institute.
The National Committee of Port Public Warehouse Keepers` Associations.
The Association of Sea and Air Port Health Authorities.
The Association of British Insecticide Manufacturers.
The Industrial Pest Control Association.

III Organizations which were invited to give oral evidence

The Research Association of British Flour Millers.
The British Food Manufacturing Industries Research Association.
The British Baking Industries Research Association.
The Cocoa, Chocolate and Confectionery Alliance Ltd.
The Food Manufacturers` Federation Incorporated.
The British Agricultural Contractors Association.
The Association of Sea and Air Port Health Authorities.
The Association of British Insecticide Manufacturers.
The Industrial Pest Control Association.
The Pest Infestation Laboratory (Department of Scientific and Industrial Research).
The Ditton Laboratory (Department of Scientific and Industrial Research).
The Cheshunt Research Station.
The East Mailing Research Station.
The Long Ashton Research Station.

IV Organizations which provided oral evidence

The Research Association of British Flour Millers.
The British Food Manufacturing Industries Research Association.
The British Baking Industries Research Association.
The Cocoa. Chocolate and Confectionery Alliance Ltd.
The Food Manufacturers' Federation Incorporated.
The British Agricultural Contractors` Association.
The Association of British Insecticide Manufacturers.
The Industrial Pest Control Association.
The Pest infestation Laboratory (Department of Scientific and Industrial Research)
The Cheshunt Research Station.
The East Mailing Research Station.
The Long Ashton Research Station.


Dated 30/09/2008

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