The Science

1. An EPA-funded study published in the November 2001 issue of Environmental Health Perspectives found that 2,4-D and dicamba (another chemical used in herbicides) are easily tracked indoors, contaminating the air and surfaces inside residences and exposing children and pets at levels ten times higher than pre-application levels. Environmental Health Perspectives 109:11, November 2001.

2. A series of studies (1990 to 1995) of Vietnam working dogs and human Vietnam vets showed increased risks of developing testicular cancer; both were potentially exposed to pesticides (picloram, malathion), phenoxyacid herbicides (2,4-D, 2,4,5-trichlorophenoxyacetic acid), zoonotic diseases, and therapeutic agents, particularly tetracycline. The risk of seminoma was approximately doubled among those dogs that had served in Vietnam in comparison with dogs in the US. Testicular degeneration, atrophy, and/or oligospermatogenesis was also diagnosed more often in dogs that served in Vietnam [odds ratio (OR) = 1.7]. Hayes HM, Tarone RE, Casey HW, Huxsoll DL. Excess of seminomas observed in Vietnam service military working dogs. J Natl Cancer Inst 82:1042-1046 (1990); Tarone RE, Hayes HM, Hoover RN, Rosenthal JF, Borwn LM, Pottern LM, Javadpour N, O'Connell KJ, Stutzman RE. Service in Vietnam and risk of testicular cancer. J Natl Cancer Inst 83:1497-1499 (1991); Hayes HM, Tarone RE, Casey HW. A cohort study of the effects of Vietnam service on testicular cancer pathology of U.S. military working dogs. Military Med 160:248-255 (1995).

3. A landmark 2004 study showed that exposure to herbicide-treated lawns and gardens (treated with phenoxy herbicides like 2,4-D) appeared to dramatically increase the risk of bladder cancer in Scottish Terriers. Glickman, Journal of the American Veterinary Medicine Association (J Am Vet Med Assoc 2004; 24:1290-1297. A follow-up study is underway. The Chemical Industry’s 24-D Task Force, however, disputes the method of this study and has posted its own studies which they assert indicate that 2,4-D is not associated with bladder cancer or any other cancers. See the industry website defending 2,4-D:

4. In 1994, Reynolds et al. found that dogs living in and around residences with recent 2,4-D treatments excreted measurable amounts of the herbicide through normal activities and behaviors for several days after exposure. Reynolds PM, Reif JS, Ramsdell HS, Tessari JD. Canine exposure to herbicide-treated lawns and urinary excretion of 2,4-dichlorophenoxyacetic acid. Cancer Epidemiol Biomark Prev 3:233-237 (1994).

5. “Animals as Sentinels of Human Health Hazards of Environmental Chemicals,” an Environmental Health Perspectives article based on a 1999 workshop sponsored by the U.S. Army Center for Environmental Health Research, the National Center for Environmental Assessment of the EPA, and the Agency for Toxic Substances and Disease Registry, included mammalian and nonmammalian species, companion animals, food animals, fish, amphibians, and other wildlife as sentinel species for human health hazard and risk assessments and for evaluating causes or mechanisms of effect, including regarding cancers that are associated with exposure to pesticides Environmental Health Perspectives 107:4, April 1999.

6. Inert ingredients problem. Lawn chemicals as applied to lawns are known to contain many toxic so called “inerts” such as toluene, xylene, hydrocarbons, cadmium, etc, which are known to cause cancer and other health hazards. The EPA does not require that these inerts be listed on the label of the lawn products. See Report of the New York State Attorney General’s Office on inerts in pesticides.

7. Read the labels. Can you ensure it will be “used as directed?” Review of the labels and data sheets of common household pesticides reveals an array of health hazards found in laboratory tests. While the EPA and manufacturers assert that the products will nevertheless be safe when used as directed, many users find it difficult to comply with the directions - such as keeping all humans and animals off of a lawn for the recommended time period after applications.