Regulatory Update: Pesticide Chlorpyrifos

Posted on March 6th, 2020

Chlorpyrifos (CFP) is an organophosphate pesticide that has been used commercially since 1965. It was invented as a substitute for the carcinogenic pesticide, Dichlorodiphenyltrichloroethane (DDT) chronicled in Rachel Carson’s Silent Spring (1962). CFP has historically been applied on agricultural crops such as corn, apples and citrus and has non-agricultural applications on golf courses and non-wood utility poles. Human exposure has been attributed to the inhalation of airborne soil from fields adjacent to residential areas and consumption of CFP treated produce. Exposure in humans inhibits the action of the key neurological enzyme cholinesterase, which is responsible for the control of nerve impulses. Side effects of exposure include but are not limited to nausea, dizziness, confusion, respiratory paralysis and death.

New Jersey has not yet banned the commercial use of CFP. The NJDEP currently has a surface water and ground water quality remediation standard in place; however, a soil remediation standard has not yet been established. Standard analytical lab analyses for pesticides regulated by the NJDEP Site Remediation Program do not usually include CFP; however, DDT is often included in laboratory analysis for this program. Since a cancellation order for DDT was not issued by the USEPA until 1972, concurrent use of DDT and CFP occurred for at least a 7-year period in the US. Property owners should consider running secondary testing for CFP if high levels of DDT are detected.


Tractor spraying pesticides on crop field

Tractor spraying pesticides on crop field


The USEPA banned residential use of chlorpyrifos in 2001. In 2012, Dr. Virginia A. Rauh of Columbia University’s Center for Children’s Environmental Health and her colleagues from Duke University, Emory University and the New York State Psychiatric Institute, examined the effect of prenatal exposure to CFP. The findings of their brain imaging study “demonstrated associations between prenatal exposure, brain structure and neurocognitive alterations at 5.9– 11.2 years of age,” which suggest that the neurotoxic effects of chlorpyrifos are long-term. “The observed brain abnormalities appeared to occur at exposure levels below the current EPA threshold for toxicity.” Subsequently, the USEPA created “no-spray” buffer zones for ground, airblast and aerial application methods around residential areas, schools and other ecologically sensitive areas but fell short of banning the commercial use of CFP. The findings of Rauh et al. 2012 were substantiated by Shelton et al. 2014. The later study observed that increased proximity to organophosphate pesticide application in residential areas led to an increase in neurodevelopment disorders, such as autism spectrum disorder (ASD), among children in the area.

Considering the mounting scientific evidence of the danger of CFP, the U.S. Ninth Circuit Court of Appeals ordered the USEPA to ban it within 60 days in August 2018. During a rehearing in February 2019, an 11-judge panel vacated the earlier ruling. US Senators Bob Menendez (D-NJ) and Corey Booker (D-NJ) and their colleagues expressed their concern regarding the USEPA’s decision to allow the continued use of CFP in a letter to the USEPA in August 2019.

Residents in New Jersey are susceptible to CFP exposure through several sources. The “Garden State,” known for its sweet summer corn, has numerous golf courses and several professional sports stadiums. Fields treated with CFP are not geographically isolated since NJ is the most densely populated state in the US; they abut residential areas throughout the state. Although it has not been definitively proven, some members of the scientific community believe there is a casual relationship between NJ’s disproportionally high 1:34 prevalence rate of ASD and the use of organophosphate pesticides. Comparatively, the prevalence rate of ASD nationally is 1:59.

Hawaii, New York and California have banned all uses of CFP and are in the process of phasing out its use over the next several years. JMS continues to monitor the status of CFP regulations in order to meet our clients’ needs. If your property has known DDT contamination, please contact JMS to determine if CFP contamination may be an unaddressed issue.



Alexandra Savino

Project Scientist



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