The environmental advocacy group Conservation Law Foundation has made good on its threat to sue Exxon Mobil Corp. , filing what it says is the first U.S. legal action aimed at holding the oil giant accountable for its well-documented climate change cover-up.

The 70-page suit , filed Thursday in U.S. District Court in Boston, alleges Exxon Mobils bulk storage and distribution terminal in Everett, Massachusetts, near Boston Harbor, continues to pollute the Island End and Mystic rivers and threatens nearby communities. The complaint also accuses the company of failing to fortify the facility to withstand climate change, including extreme weather events and rising sea levels.

The lawsuit, which seeks unspecified civil penalties and injunctive relief, comes as Exxon Mobil faces numerous investigations into whether the company lied to investors and committed fraud by covering up the risks of climate change for decades. The attorneys general of New York and Massachusetts are probing the company, and the Securities and Exchange Commission has begun an investigation into how Exxon Mobil values future projects amid climate change and plunging oil prices.

Communities were put in danger and remain in danger , all to cut costs for one of the most profitable corporations in the world, Bradley Campbell, president of Boston-based Conservation Law Foundation, said in a statement. Its time to make Exxon answer for decades of false statements to the public and to regulators and ensure that its Everett facility meets its legal obligation to protect thousands of people and the Boston Harbor estuary from toxic water pollution.

In 2009, a subsidiary of Exxon Mobil was ordered to pay more than $6.1 million for allowing 15,000 gallons of diesel fuel to spill into the Mystic River. The lawsuit alleges the company continues to violate the Clean Water Act and other federal laws by discharging toxic pollutants.