would incur an annual cost of $1.6 billion to $4 billion. Regulation Massachusetts Legislation passed in 2014 requires gas suppliers to make greater efforts to control some of the 20,000 documented leaks in the US state of Massachusetts. The new law requires grade 1 and 2 leaks to be repaired if the street above a gas pipe is dug up, and requires priority be given to leaks near schools. It provides a mechanism for increased revenue from ratepayers (up to 1.5% without further approval) to cover the cost of repairs and replacement of leak-prone materials (like cast iron and non-cathodically protected steel) on an accelerated basis. The law sets a target of 20 years for replacement of pipes made from leak-prone materials if feasible given the revenue cap; , Columbia Gas of Massachusetts (formerly named "Bay State Gas"), Berkshire Gas, Liberty Utilities, National Grid, and Unitil say they will meet this target, but NSTAR says it will take 25 years to complete. Leaks, statistics on leak-prone materials, and financial statements are reported annually to the Department of Public Utilities, which also has responsibility for rate-setting. Additional proposals not included in the law would have required grade 3 leaks to be repaired during road construction, and priority for leaks which are killing trees or which were near hospitals or churches. An attorney for the Conservation Law Foundation stated that the leaks were worth $38.8 million in lost natural gas, which also contributes 4% of the state's greenhouse gas emissions. A federal study prompted by US Senator Edward J. Markey concluded that Massachusetts consumers paid approximately $1.5 billion from 2000–2011 for gas which leaked and benefited no one. Markey has also backed legislation that would implement similar requirements at the national level, along with financing provisions for repairs. History Catastrophic gas leaks, such as the Bhopal disaster are well-recognized as problems, but the more-subtle effects of chronic low-level leaks have been slower to gain recognition. Other contexts In work with dangerous gases (such as in a lab or industrial setting), a gas leak may require hazmat emergency response, especially if the leaked material is flammable, explosive, corrosive, or toxic. See also Gas detector List of pipeline accidents in the United States 2022 Nord Stream pipeline sabotage References External links naturalgaswatch.org (advocacy blog) City Maps of Gas Leaks reported by utilities in Massachusetts Somerville and Cambridge gas leaks surveyed by mobile detection vehicle