Maryland to resume use of pesticide after EPA testing doesn’t detect PFAS

Maryland will once again spray pesticide Permanone 30-30 to control mosquito populations, after EPA testing determined it does not contain dangerous PFAS, officials said.

The Maryland Department of Agriculture temporarily halted use of the pesticide in the state this year “out of an abundance of caution,” after testing by an outside lab, commissioned by nonprofit groups, found 3,500 parts per trillion of one type of PFAS, and 630 parts per trillion of another, said MDA spokesman Jason Schellhardt.


But testing by EPA scientists at Fort Meade returned a different result.

PFAS, per- and poly-fluoroalkyl substances, are also known as “forever chemicals,” because they can linger in the human body for long periods of time. Laboratory tests have shown that accumulated PFAS can cause tumor growth in animals, in addition to problems with kidney, liver and reproductive function. The most consistent findings from human epidemiology studies show that PFAS exposure can cause increased cholesterol levels, but studies have also shown evidence of problems related to infant birth weights, thyroid and immune system problems and cancer.


The chemicals were used widely in the U.S. starting in the 1940s to manufacture items like nonstick cookware and stain repellent. Military bases and other facilities often used firefighting foams that contained the chemicals, prompting fears about groundwater contamination nearby.

Over the summer, EPA tested several Permanone 30-30 samples for 28 different varieties of PFAS using a new method called the “oily matrix” test.

Ruth Berlin, executive director of the Maryland Pesticide Education Network, one of the groups that commissioned the earlier test of Permanone 30-30, said she wasn’t satisfied by the new results from EPA scientists. Eurofins, the lab that conducted that initial testing, did not respond to a request for comment about the new results from the federal government.

“EPA tested for 28 PFAS. Now, that sounds like a lot. However, there are over 9,000 PFAS products. So a whole lot of other PFAS weren’t tested for,” Berlin said.

As a result, Berlin said Maryland or the EPA needs to require pesticide manufacturers to conduct in-depth PFAS screenings before placing their products on the market.

“We think it’s incumbent on EPA to be protective rather than reactive, and to really fulfill their mission to ensure that human health and the environment are protected from PFAS,” Berlin said.

So far, the EPA has conclusively detected PFAS in one mosquito control product, called Anvil 10+10. That contamination was blamed on fluorinated plastic containers used to store the pesticide.

Initially, scientists at the EPA’s Analytical Chemistry Branch in Maryland found evidence of one PFAS compound in Permanone 30-30 samples obtained from Maryland, which had been stored for two years, and were visibly discolored, according to an EPA report. But further testing determined that was a false positive. No PFAS were detected in samples obtained in May directly from manufacturer Bayer at different points in production.


The company did not make any modifications to the product between the Eurofins test in March and the EPA testing, said Bayer spokesman Kyel Richard.

“We are reviewing the EPA’s new testing method released yesterday, and we will continue to follow all guidance from the Agency,” Richard wrote in an email.

PFAS have drawn increasing concern from environmental groups over time.

Dating back to 2019, Maryland’s Department of the Environmental has tested water from more than 100 treatment plants in the state. So far, PFAS levels above EPA’s threshold have been detected at wells in Westminster and Hampstead in Carroll County, which were taken off line for investigation. EPA has set a lifetime health advisory for two types of PFAS in drinking water at 70 parts per trillion. In other words, the agency believes that daily exposure at or below that level won’t cause adverse effects.

MDE is also conducting testing on Chesapeake Bay oysters, since PFAS could accumulate in their tissue as they filter potentially contaminated water from the estuary. Testing of oysters in the St. Mary’s River, Patuxent River and Fishing Bay in 2020 found concentrations below the detection limit.

This summer, a study released by the Environmental Working Group determined PFAS had been detected at several different military bases in Maryland bordering the Chesapeake Bay, including the Army’s Aberdeen Proving Ground, the Air National Guard Base at Martin State Airport in Middle River and the U.S. Naval Academy in Annapolis, as well as Southern Maryland’s U.S. Naval Research Laboratory’s Chesapeake Bay Detachment and Blossom Point Tracking Facility and the Naval Air Station Patuxent River. Some of those detections were under the EPA’s threshold, like at Aberdeen, but others soared above it. A reading at the Naval Research Laboratory, for instance, found 234,000 parts per trillion of one PFAS chemical in groundwater.