The price tag for cleaning up two petroleum refineries in northern New Jersey will cost Exxon Mobil much more than the $225 million settlement brokered by Gov. Chris Christie's administration, but critics of the proposal say it could be years until it's clear how much the company eventually will have to pay. The Department of Environmental Protection posted details of the proposed settlement with the Texas-based oil company on Monday but did not outline what it plans to do or how much the clean-up will cost.