The Environmental Protection Agency says it will do more studies on the effectiveness of General Electric's cleanup of the Hudson River. 

The agency has begun analyzing about 1,800 sediment samples from the river, which were taken by the state. GE asked the federal agency about a year ago for a certificate of completion of its $1.7 billion cleanup effort to remove PCBs from the river, claiming it completed its cleanup in 2015.

But last month, Governor Andrew Cuomo and New York Attorney General Eric Schneiderman said they would sue the federal government if the EPA issued a certificate of completion to GE.

The EPA's regional administrator said it's "imperative'' for the agency to expand its efforts to ensure the river is fully fixed.