THE CONSERVATION LAW Foundation notified National Grid on Tuesday that it and several other environmental groups intend to sue the utility for failing to promptly fix methane gas leaks that are killing off trees and risking the possibility of fires and explosions.
In the letter to top National Grid officials, the foundation accused the company of improperly disposing of “hazardous waste” and violating federal pipeline regulations and state environmental laws. The foundation said it is seeking financial penalties of hundreds of thousands of dollars a day and a commitment to address leaks much more quickly or reduce the use of natural gas all together.
The Conservation Law Foundation said its lawsuit will be based on data submitted by National Grid to state regulators and the foundation’s own field work testing methane levels in the Boston area.
Over a seven-day period in July, the foundation said it identified 15 locations where methane gas concentrations posed the risk of fire or explosion. The biggest concentrations were found at a building foundation at 1562 Dorchester Avenue in Dorchester (40 percent), a manhole at 4109 Washington Street in Roxbury (20 percent), and the foundation of the Liberty Mutual tower at 157 Boylston Street in the Back Bay.
Other worrisome spots, according to the foundation, included a manhole at the intersection of Adams Street and Whitten Street in Dorchester (11 percent), the foundation at 39 Heard Street in Chelsea (9 percent), and a manhole at 1916 Dorchester Avenue near Ashmont Station in Dorchester (6 percent).
CLF found more than 200 public shade trees dead or dying from methane poisoning from leaking gas pipelines.
According to the CLF letter, a Grade 1 methane gas leak is one that “represents an existing or probable hazard to persons or property,” and, if present, National Grid must “immediate[ly] commence[] repair-and continuous action until the conditions are no longer hazardous, the source of the leak is eliminated, and permanent repairs have been completed.”
The foundation said National Grid failed that standard 879 times since 2019 in Boston and Chelsea.
The foundation also identified 290 instances where National Grid failed to deal with Grade 2 methane gas leaks in a timely manner and 59 instances when Grade 3 leaks were not corrected within parameters set by state law.
“National Grid’s leak data shows it allows hazardous Grade 1 leaks to continue leaking for more than 2 ½ years. Upon information and belief, further investigation will indicate more hazardous Grade 1 leaks for which National Grid did not immediately commence repair and continuous action until elimination of such leaks,” CLF said.
National Grid, which operates Boston Gas, declined to comment.
CLF is joined in the legal action by four other advocacy groups — GreenRoots, Boston Parks Advocates, Mothers Out Front, and Affected Citizens.