Pest control personnel in Boston and New York have deployed a new weapon in the war against urban rats: dry ice. Workers from Boston's Inspectional Services Department first used the substance back in April, The Boston Globe reported. So far, the agency has seen great success using the substance.
Agency personnel purchase the dry ice – essentially solidified carbon dioxide – in bulk and use it to plug the entrances and exits of underground rat burrows. Slowly, the substance melts and fills the tunnels with gas, suffocating and killing the rodents inside.
Boston city officials say the methodology is more cost-effective than spreading expensive poison and ultimately more humane. Researchers from Harvard University and the Massachusetts Institute of Technology helped develop the technique.
"It's simple science," William Christopher, commissioner for the ISD, told the Globe. "It has not hurt anyone or any other wildlife or plant life. Based on everything we've seen so far, it's been excellent."
Like many major metropolitan areas, Boston has experienced an uptick in rat activity over the last year, USA Today reported. New York is dealing with similar problems. Residents in the city have filed more than 3,000 rodent complaints so far this year.
In July, officials from the Department of Health and Mental Hygiene started filling rat burrows in Columbus Park, Seward Park, J. Hood Wright Park and Tompkins Square Park with dry ice, the New York Daily News reported. The effect was immediate, as rodent populations in these areas dropped significantly. This excited locals and sated the environmentally conscious who have long argued against the city's use of commercial grade rat poison which can harm pets and small wild animals.