Last fall, news reports surfaced of pest management professionals (PMPs) in three major U.S. cities successfully using dry ice (carbon dioxide, or CO2) to manage rats.
“Dry ice is an effective way to control rats underground,” says Dr. Jim Fredericks, vice president of technical and regulatory affairs for the National Pest Management Association (NPMA), and PMP’s monthly “Callback Cures” columnist.
But because dry ice was not registered for use as rat control, and therefore violated the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), it didn’t take long for the U.S. Environmental Protection Agency (EPA) — which is responsible for its enforcement — to put a stop to the practice.
At the end of June, however, the EPA granted Bell Laboratories federal registration for a product containing dry ice. Once the product is registered in their states, PMPs may use this newly approved option.
“It is another tool in the PMP’s integrated pest management toolbox, and can be used alongside bait, sanitation and exclusion programs to help clients control rats on their property,” Dr. Fredericks says.
The use of dry ice in this manner gained attention recently. Residents of Boston, Chicago and New York City complained to city officials about an increase in rat activity, reported USA Today in April 2016. The problem was attributed to several factors, including prevalent food sources, dog owners not disposing of dog waste, and warmer winters. City officials in Boston gave dry ice a try, and were pleased with its performance and price, USA Today said, and Chicago and New York soon followed suit. Seven months later, the newspaper reported that the EPA notified cities using dry ice that they were violating federal law.
When the EPA advised users dry ice was an unregistered product and violated FIFRA, the NPMA notified its members, Dr. Fredericks says.
In early 2017, the NPMA approached the EPA about the issue, he says. The association also discussed the use of dry ice for rat management with PMPs, researchers and registrants. When Bell Laboratories submitted an application to the EPA demonstrating the efficacy of the pelletized form of dry ice, the NPMA circled back to the EPA.
“State and local governments were clamoring for the EPA to find a way to approve dry ice, through a special, local need; emergency; or traditional registration,” Dr. Fredericks says. “The NPMA strongly encouraged the EPA to register the product. The registration was approved relatively quickly, most likely due to having an innovative, willing registrant, coupled with a well understood, effective, low-toxicity product.”
The use of dry ice is most effective when dropped into subterranean rat burrows located away from structures. It could be used in outdoor residential commercial and municpal settings, including public parks, Dr. Fredericks says. But he notes that PMPs will only be able to use the labeled product when it is approved in their particular states.
Bell Laboratories says it is working on state registrations and will provide a more comprehensive update, including launch details, soon.
It’s also important to note that dry ice is not registered for use on any other pests, with one exception: CO2 gas is registered for use against stored product pests as a fumigant.