To the Editor

Paediatricians, physicians and parents alike should be assured that decisions of government pesticide regulators are made on the basis of the most modern science-based risk assessment and risk management principles.

The article “Pesticide assessment: Protecting public health on the home turf” by Sears et al (1) draws into question Health Canada’s Pest Management Regulatory Agency (PMRA) science-based risk assessment of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D).

The PMRA’s proposed regulatory decision builds on an unprecedented number of science-based risk assessments around the globe. With these assessments, incredible confidence has been gained over the past several years in the knowledge and understanding that 2,4-D does not present a risk to human health when used for intended purposes.

Agencies mandated with protecting human health, including the United States Environmental Protection Agency (1997 and 2005), European Commission (2001), New Zealand (2000 and 2003), World Health Organization (1996, 1997, 1998 and 2003) State of Washington (2001) and National Cancer Institute (Alavanja, 2003 and 2004) as well as numerous expert panel reviews (Munro, 1992; Johnson, 1996; Kogevinas, 1997; Gandhi, 2000; Kennepohl, 2001; Garabrant, 2002; Dost, 2003) have consistently concluded that 2,4-D does not present a human cancer risk.

In its decision released on August 8, 2005, the US EPA concluded that acute and short-term margins of exposure for homeowner applications of 2,4-D to lawns were “not of concern”. (Stated 12 times in the referenced document [2].)

We note with interest that although the authors referenced the EPA science-based risk assessment of modern data (Sears et al, references 2 and 27) – they did not report in their article EPA’s conclusion that 2,4-D is not a cancer risk.

Paediatricians wishing to further their knowledge in this matter would be well served by carefully examining these two reference documents, which may be found at <http://www.epa.gov/pesticides/reregistration/24d/>.

We fully support a public health objective of reducing exposure risks to harmful compounds. However, this cause is not advanced by the advocacy of misleading theories, particularly when these are supported by a selective reporting of the evidence.