BOSTON (AP) — Massachusetts residents may soon feel the effects of a new law that aims to hold public utility companies accountable for emergency response services and notifications during power outages.

Gov. Deval Patrick signed the storm response bill into law Monday night behind closed doors at the Statehouse. The law immediately took effect upon the governor's signing.

The legislation aims to improve emergency response services in Massachusetts by requiring public utility companies to establish a well-staffed call center during major storms and coordinate with the Massachusetts Emergency Management Agency when implementing an emergency response plan, among other things.

It would also require the companies to pay an assessment charge, which cannot be passed onto customers, to help fund the state's Department of Public Utilities storm investigations. The law does not specify how much the charge would be.

Neither the charge nor fines for inadequate storm response would be passed on to consumers. Fines would be returned to consumers.

The measure was developed after major power outages following Tropical Storm Irene in August 2011 and a surprise October snowstorm. Massachusetts Attorney General Martha Coakley said the new law will ensure that rate relief is provided to consumers affected by poor storm response. She said it will also improve public safety by requiring utility companies to "implement better defined plans to communicate with customers and local municipal officials" regarding storm response.

Coakley's office has been investigating the storm response efforts of major Massachusetts public utility providers following these two storms. The attorney general has recommended that the state's Department of Public Utilities impose $16 million in fines on National Grid, $9.7 million on NSTAR and $4 million on Western Massachusetts Electric Company for inadequate response efforts. The companies are disputing the recommended fines.