A new study of natural gas infrastructure in Connecticut says harmful amounts of methane are leaking from aging underground gas pipes. Methane is the main part of natural gas. Like carbon dioxide, it’s a greenhouse gas, trapping heat in the atmosphere and contributing to global warming. And one way methane can leak here in New England? From old buried pipes. In Hartford, his team found enough methane leaking from pipes each day to heat more than 200 homes. Leaks were also found in Danbury and New London. Connecticut Natural Gas and Southern Connecticut Gas, which are owned by Avangrid, also the parent of United Illuminating, declined a request for an interview about the study. And while companies are supposed to step in to fix major leaks, especially if they pose safety risks, Howarth says the gas industry doesn’t have much incentive to fix other methane leaks. But the utilities said they remain vigilant of methane leaks in Connecticut towns.