The Pyrethroid Working Group (PWG) today (Jan. 13, 2020) issued the following statement in response to a recently published study, “Association Between Exposure to Pyrethroid Insecticides and Risk of All-Cause and Cause-Specific Mortality in General U.S. Adult Population (Bao, et al) .”

As an organization dedicated to research, environmental stewardship and public health, the Pyrethroid Working Group (PWG) has conducted an initial review of the study in which the authors suggest a link between pyrethroid insecticides and cardiovascular disease (CVD) or other cause-specific mortality.

The overwhelming body of science does not support claims that pyrethroids pose a danger to the public or environment when they are applied according to US EPA label requirements. In fact, pyrethroids play a vital role around the world in protecting humans from pests that may carry infectious diseases, including ticks that spread Lyme disease and mosquitoes that can carry West Nile Virus. PWG has invested heavily in research, environmental stewardship and product responsibility over the past two decades.

Despite issues with some of the underlying assumptions in this study, the results, coupled with the existing body of science, demonstrate that pyrethroids as a class do not cause cardiovascular disease or other events leading to mortality.

While Epidemiological studies can provide valuable insights into the human-relevance of environmental or pathogenic exposures, careful consideration must be paid to the study design and potential confounders should be identified to allow for proper interpretation. Furthermore, findings from such studies should be independently replicated to provide confidence in the observed association(s). This study has a variety of significant limitations:

  • The analysis did not account for family history of cardiovascular disease – even though genetics represent one of the most significant factors for CVD.
  • The study relied on self-reporting for key variables that are known to contribute to CVD-related mortality, such as smoking, alcohol consumption and physical activity. Potential recall biases in self-assessments such as these can severely impact results.
  • There was no definitive exposure determination in the study. The metabolite used as an indicator is also found in the environment as a plant and environmental degradate and is not itself of concern.
  • The determination was also based on a single urine spot sample, which cannot support conclusions on long-term exposure and does not adjust for factors such as body weight and sex.
  • Study results do not align with the significant body of evidence that does not show these effects, even at extremely high exposure levels.

Pyrethroids, which are synthetic chemicals derived from chrysanthemums, are among the most studied of all pesticides used in commerce. The collective body of evidence for pyrethroids supports their safety to humans and the environment. To learn more and view the science for yourself, visit the Pyrethroids Resource Center at


The Pyrethroids Resource Center is one of several public education programs funded by the Pyrethroid Working Group, an industry alliance that conducts research and promotes the responsible use, storage and disposal of pesticides commonly used in the garden and outside home as a way to help protect urban waterways and environment. The Pyrethroid Working Group is comprised of following companies: AMVAC Chemical; BASF Corporation; Bayer CropScience; FMC Corporation; Syngenta Crop Protection; and Valent U.S.A. LLC.