NIOSH Study Shows Scope of Illness Tied to Two Common Herbicides
Although most of the illnesses related to paraquat and diquat were low to moderately severe—health effects commonly included skin, eye, or neurological symptoms—these two herbicides make up 85 percent of herbicide-related deaths in the United States.
A NIOSH study looking at illnesses and herbicide-related deaths discovered that most cases of illness related to paraquat poisoning were low to moderately severe. According to the agency's news release, the study found 300 paraquat-related and 144 diquat-related acute illnesses were reported in 35 states and one U.S. territory; 76 percent of paraquat-related cases were work-related.
Although most of the illnesses were low to moderately severe—health effects commonly included skin, eye, or neurological symptoms—these two herbicides make up 85 percent of herbicide-related deaths in the United States. Among the reported cases, 43 individuals had ingested paraquat and 25 ingested diquat. Most such cases were unintentional and frequently occurred because the pesticides were improperly stored, such as in beverage bottles.
"This is really the first time we've looked at the extent of illness caused by these herbicides," said NIOSH Director Dr. John Howard, M.D. "We now know that all of the cases of illness and death related to these products are preventable, which will help us identify ways to better protect both the workers who need to use these products as part of their job and others exposed to these potentially harmful chemicals."
The researchers examined combined data from three sources from 1998 to 2011: the NIOSH Sentinel Event Notification System for Occupational Risks (SENSOR)-Pesticides Program; the California Department of Pesticide Regulation Pesticide Illness Surveillance Program; and the EPA Office of Pesticide Programs' Incident Data System. Other data from a national database, the National Poison Data System, was used for national trends of paraquat- and diquat-related illnesses.
Failure to wear PPE, especially eye protection, was the most common reason people became sick from paraquat, while other causes included drift from the pesticide application site and accidental spills or splashes. For diquat, the most common cause of illness was application equipment failure, followed by accidental spills or splashes. "When less harmful weed control options aren't an option, these findings suggest that additional training and stricter compliance with label instructions to ensure proper herbicide storage and PPE use are important measures to help prevent illness or even death," said NIOSH Medical Officer and senior study author Dr. Geoff Calvert, M.D., MPH.