Letter addressed to Charles Caccia

Letter addressed to Charles Caccia

June 8, 2000

The Honourable Charles L. Caccia

House of Commons

180 Wellington, Room 642

Ottawa, Ontario K1A OA6

Dear Chairman Caccia:

I would like to take a bit of your time to respond to the allegations made against the herbicide 2,4-0 in the report of the Standing Committee on Environment and Sustainable Development, Pesticides: Making the Right Choice for the Protection of Health and the Environment- I apologize in advance for the length of this letter, but the allegations made cannot be addressed briefly.

To introduce myself, I am a self-employed agricultural consultant who serves as Executive Director of the 2,4-D Task Force, that international group of companies, which, as allowed by law, must jointly fund the more than 270 new research studies required by U-S. EPA and requested by the Canadian PMAA under the Canadian and American pesticide reregistration programs 2,4-D, in addition to being the most widely used agricultural herbicide worldwide is also the most widely used lawn care herbicide in Canada, where it was introduced in 1947. I am a dual national (Canadian/American), and did my undergraduate studies at the University of Windsor.

The allegations made in support of the proposal to ban the “cosmetic” use pesticides in Canada, as I understand them, are as follows:

Pesticides are inadequately researched. I can comment only on the widely used herbicide 2,4-D, however all registered pesticides must have met rather exhaustive research standards set by regulatory agencies throughout the world (see my comments on the data package for chlorpyrifos (Dursban) later in this letter). Additionally, pesticides are reviewed by such international agencies as the Wor1d Health Organization (WHO) and the U.N. Food and Agricultural Organization (FAO), and reports from these agencies are readily available (and are attached to this letter).

2,4-D, in addition to being the most widely used agricultural herbicide worldwide, was the first selective herbicide developed (a selective herbicide controls weeds in a crop without harming the crop), something which stimulated an enormous amount of research on 2,4-D all over the world. The reason for the huge research effort has been.

2,4-D’s enormous impact on increasing world food production while reducing food production costs. A U.S. Government study (attached) concluded that should 2,4-D no longer be available, the cost to consumers, in the form of higher food prices, and to users (farmers) in the form of higher production costs, would total U.S. $1 ,683 million annually in the U.S. alone. An earlier study initiated by the Canadian Government (An Economic Assessment of the Benefits of 2, 4-D in Canada, Guelph. Ontario, September, 1988) concluded that the loss of 2,4-D would cost Canadians a third of a billion dollars annually.

While I don’t know what the total number of research studies currently is (it is reported to be in the tens of thousands), I can confirm that the toxicology data base alone exceeds 4.000 Qeer-reviewed. published studies. plus hundreds of unpublished studies which the manufacturers must fund for the various regulatory 8~es throughout the world. Additionally, there are now more than 100 peer-reviewed. published epidemiologic (human) studies pertinent to 2.4-D. If anything, 2,4-D seems to be researched ad infinitum. The reason anti-pesticide activists keep insisting on more research is that they either have little comprehension of the extent of the current data package or the fact that the weight of today’s scientific evidence simply does not support their allegations.

The bulk of the research has been “done by industry” and is therefore biased and should not be taken seriously. As mentioned above, this Task Force was formed, as allowed by law. to fund the more than 270 new research studies requested by the PMRA and the U.S. EPA under the Canadian and American pesticide reregistration programs. These research programs, which apply to pesticides registered prior to November, 1984, have cost in excess of U.S. $30 million for 2,4-0 alone- Yet this Task Force did not conduct a single study, which by U.S. law, must be done by EPA Good Laboratory Practice (GLP) qualified laboratories. These are laboratories which meet stringent EPA specifications and controls. U.S. EPA carefully reviews all studies for GLP compliance; an unintentional GLP violation can invalidate the study, requiring the study to be repeated, which is very costly. An intentional GLP violation (such as the understating of toxicity) is a violation of federal law, a felony. These laws are enforced, so GLPs are taken very seriously by both the industry involved and the laboratory doing the work. This Task Force has contracted the required 2,4-D research studies to more than thirty EP A/G LP qualified laboratories for completion under the reregistration program. The last of these studies was submitted to EP A in December, 1995, although additional work is ongoing. Canadian PMRA has either received copies of the complete studies, some of which run 5,000 pages or more, or they have received copies of U.S. EPA’s critique of the study in place of the entire study, at PMRA’s option.

2,4-D causes cancer in laboratory animals. This allegation is repeatedly made by activist groups. However, the toxicology data base now demonstrates conclusively that 2,4-D does not cause cancer in laboratory animals. Attached is an EPA review of several GLP lifetime mouse and rat feeding studies and a re-review of a multi- generational reproductive study in rats. This review is important because it contains the current EPA toxicology profile sheet on 2,4-0. As you will note, it describes 2,4-0 as both non-carcinogenic and non-mutagenic. Some of the animal feeding studies required the feeding of massive amounts of 2,4-0 to the test animals daily over their expected lifetime. Copies of several current peer-reviewed, published reviews of the numerous 2,4-0 animal studies are attached- PMRA has requested and received copies of this same research- When activists make the charge that 2,4-0 causes cancer in laboratory animals, they should be asked to cite the study supporting the allegation. What they typically cite are articles from activist publications, such as the Journal of Pesticide Reform, rather than actual research studies.

2,4-D is a human carcinogen. As previously indicated, there are now more than 100 epidemiologic studies (human studies) pertinent to 2.4-D. While the case-control studies are somewhat ambivalent (which is not uncommon when dealing with a non-carcinogen or a very weak carcinogen), the more powerful cohort studies support the toxicology and do not support those case-control studies which suggest an association between 2,4-0 exposure and cancer. Case-control studies are short term studies based mainly on questionnaires and telephone interviews. Exposure to the studied chemical is assumed based on the type of work done by the people who make up the cases and controls in the study, and no actual exposure measurements are made. Cohort studies are long term studies (20 years or more) where the participants’ actual medical records are followed and, in many cases, exposure studies are actually conducted. This is why the most recent EPA review of the 2,4-0 toxicology and epidemiology data bases (which is attached) has concluded (for the 4th time) that 2,4- D should remain a Class D compound. Under EPA’s classification of carcinogenicity, Class A compounds are known carcinogens”, Class B compounds are probable carcinogens” and Class C compounds are -possible carcinogens. A “D” classification means that there is insufficient evidence of carcinogenicity in the data package to place the compound in any of the three higher classifications. The recent WHO/FAO review of 2,4-D (attached) reaches the same conclusion. Activists cite only the few case-control studies suggesting an association between 2,4-0 and cancer and disregard the many studies which do not support the alleged association. This widely used tactic is known as “selective science.”

2,4-D is an “endocrine disruptor”. This is a relatively new a/legation. The endocrine disruption hypothesis (there is still no hard scientific evidence that endocrine disruptors exist in the environment) was popularized by the anti-pesticide activist Theo Colburn in her best-selling book, Our Stolen Future (1996). Ms. Colburn, who is employed by the World Wildlife fund, suggests that there are minute quantities of very persistent compounds in the environment, both pesticides and industrial chemicals, which when combined with similar chemicals, have powerful hormonal effects on humans and wildlife, causing birth defects, mutants, cancers of the breast and reproductive system etc- She cites the long-banned chlordane and DDT as examples. (She does not identify 2,4-D, which she mentions only once in her book, as an Mendocrlne disruptor- .) This hypothesis appeared to be strongly supported by a Tulane University study published three months later (Arnold et al, Synergistic Science, vol. 272, 1996). That study allegedly showed that certain very persistent chemicals present in the environment In very small quantities, when combined with similar chemicals, exhibited remarkable synergistic activity, with the combinations being as much as 1600 times more potent than the individual chembls alone. ThiS study received extraordinary media coverage in Canada and the U.S. , creating widespread public concern. However, other researchers (and the author himself) were unable to replicate the results reported in the study, forcing the author to ask that the study be withdrawn from the scientific literature and prompting his resignation from the university .The retraction of this widely publicized study received almost no media attention, and activist groups still cite It as strong evidence of the dangers of “endocrine disruption” Other studies designed to support the endocrine disruptor hypothesis, (such as Plasma Organochlorine Levels and the Risk of Breast Cancer , Hunter et al, New England Journal of Medicine, Vol. 337, 1997) have failed to do so. Widely publicized findings of deformities in frogs found in some parts of the U.S. were promptly blamed on Mendocrlne disruptors,. although later studies identified other environmental factors as the cause (excessive exposure of the frog eggs to ultraviolet light in sunlight -frog eggs are extremely sensitive to ultraviolet light and can be easily damaged).

Yet “endocrine disruption” is still ballyhooed by activists as a major environmental concern, and 2,4-0 is routinely described in activist literature as a “known endocrine disruptor” (see the web sites for the Canadian World Wildlife Fund and the Toronto Environmental Association or TEA). When asked for the basis of their contention that 2,4-0 is a ~known endocrine disruptor” these organizations cite each other and other activists organizations, such as Greenpeace, The National Campaign for Pesticide Policy Reform etc. , rather than scientific studies.

In 1997, as a result of public concern caused by Ms. Colbum’s book and the Tulane study, the U.S. Congress ordered U.S. EPA to develop testing procedures for “endocrine disruption” for tens of thousands of chemicals. In 1998 EPA issued their list of the first 168 chemicals to be tested. These chemicals were divided Into a number of categories. For example, Category One was made up of chemicals “suspected of endocrine disruption,” Category Two was for chemicals “unknown as to endocrine potential,” and Category Three was for chemicals “known to have no endocrine effect.” 2,4-0 was placed in Category Three, based on the following EPA criteria:

“1. Substances known to have no hormonal activity, i.e., negative activity to estrogen, androgen and thyroid receptor transactivation assay (EAT negative}.

2. Substances with adequate and extensive In viva data bases, including developmental and reproduction studies.”

Unlike alleged “endocrine disruptors,” 2,4-D is not persistent in the environment, having a half-life of about seven days. It eventually breaks down to carbon, carbon dioxide and a bit of chlorine, all of no toxicological significance. This is easily confirmed in the scientific literature.

In August, 1999 an expert panel convened by the U.S. National Research Council found no persuasive evidence that chemicals in the environment are disrupting hormonal processes in humans or wildlife.

The chJorpyrifos (Dursban) data package. The existing EPA registrations for chlorpyrifos are based on rather extensive data obtained from product testing on paid human volunteers given nontoxic doses. The No Observable Effect Level (NOEL) is based on such data. The present U.S. administration (Mr. Clinton) has decided, for political reasons, that human testing is “unethical” and such data, while acceptable for medical research, cannot be used for pesticide registration. This position has long been demanded by anti-pesticide activist groups, for obvious reasons (i.e. the large reduction in chlorpyrlfos uses which resulted). If only animal studies can be used, the large safety margins required when extrapolating animal data to human exposure will necessitate a severe reduction in the number of registered uses for the pesticide in question. But the decision was based on “ethics” or politics, rather than on science. In other words, no new information was developed which suggested chlorpyrifos was more dangerous than previously believed; the ground rules were simply changed.

I am enclosing a copy of a comprehensive study of 2,4-D and the other phenoxy herbicides conducted by the U.S. Department of Agriculture in conjunction with fifty state universities (one representing each of the fifty states), done at the request of EPA. This 200 page report concludes, on page two, “The phenoxy herbicides are low in toxicity to humans and animals, ..No scientifically documented human health risks either acute or chronic exist from the approved uses of the phenoxy herbicides. After more than fifty-four years of extensive use throughout the world, this surely is a remarkable safety record. A CD-ROM containing some 1,000 pages of peer-reviewed studies, EPA and WHO reports etc. is also attached.

If you have any further questions concerning 2,4-D I would very much like to hear from you.

Sincerely,