A chemical plant sits along the Kanawha river in Marmet, W.Va., Jan. 14. While no one became seriously ill from a chemical spill Jan. 9 at a storage facility in Charleston, W.Va., legislation has been proposed to close a loophole regarding above-ground storage tanks.

CHARLESTON, W.Va. — West Virginia Gov. Earl Ray Tomblin and U.S. Sen. Joe Manchin urged passage of a stricter chemical storage regulatory program Monday after a spill contaminated the water supply for 300,000 people.

The bill aims to address shortcomings that allowed 7,500 gallons of coal-cleaning chemicals to seep into the Elk River on Jan. 9. Freedom Industries, which owned the plant that leaked the chemicals, filed for Chapter 11 bankruptcy Friday.

Freedom Industries' safety flaws went largely undetected, because as a facility that neither manufactured chemicals, produced emissions, or stored chemicals underground, it was not subject to environmental regulations, state Department of Environmental Protection officials have said. The chemical that spilled also wasn't deemed hazardous enough for additional regulation. The material flowed 1.5 miles downstream and made it into West Virginia American Water Co.'s water supply.

The department made several routine visits to the Charleston site between 2002 and 2012, but found no violations.

The governor's bill, which hasn't been filed yet, would mandate annual inspections of above-ground chemical tanks, and would require water systems serving the public to draft emergency plans in case of spills.