"It's hard to pin the exact dollar amount on it but suffice it to say we've suffered a loss and we've initiated this action because we'd like to recover some of that money," said DiNapoli. "We think the loss is very much tied to poor decisions on the part of corporate leadership--failure to assess risk-gap adequately and failure to have plans in place to deal with an incident like this."

DiNapoli said there is a precedent for pension funds filing class-action law suits against corporations, the most recent following the meltdown of the national housing and mortgage markets.

"Our most recent success in that regard was with our Countrywide suit. We were lead plaintiffs in the class-action suit against Countrywide and recovered over $600 million for the class in that regard so we don't take these steps lightly, but where there's a situation that really cries out for attention and this one does."

New York's pension fund is the nation's third-largest with more than $132 billion in assets. It generates retirement benefits for state and local government employees, police officers and firefighters. Other state pension funds have also been stung by the decline of BP stock. The California Public Employees' Retirement System has seen its investment in the giant drop in value by more than $200 million.