(Harrisburg) -- Two state senators say they want to tighten the Commonwealth's rules for cleaning up environmentally sensitive properties. The lawmakers are proposing a bill to require owners of certain commercial properties to conduct environmental remediation -- if the use of the property changes. Erik Arneson is a spokesman for Senate Majority Leader Dominic Pileggi, who co-sponsored the measure. He says current law only requires cleanup when properties are sold or abandoned. "There is a gap in the law when it comes to situations where the owner stays in place, but makes really significant changes to how that property is used," Arneson says. He says workforce reductions of about two-thirds or idling of a like amount of equipment are changes that could trigger a remediation under the new bill. He says there is particular concern about the future of oil refineries in the Philadelphia area and the environmental challenges those sites may pose.