CHARLESTON, W.Va. (AP) -- After a 2014 chemical spill polluted drinking water for more than 300,000 people in West Virginia, lawmakers there quickly mandated tighter surveillance of the state's chemical storage tanks. It revealed dozens of tanks that shouldn't have been in service still posed a potential threat to drinking water for more than 134,000 people downstream. Many were corroded and a few were filled with hazardous chemicals.
But under pressure from industry, lawmakers have already exempted thousands of tanks from the law.
A state survey found about 50 storage tanks near waterways shouldn't have been in service.
State environmental regulators identified the tanks under a law passed following the January 2014 chemical spill at Freedom Industries. The leak from a corroded tank protected by a porous containment wall left 300,000 Charleston-area residents without clean tap water for four to 10 days.
The tank tally was one of the law's first requirements, and it quickly yielded results. Most of the shoddy tanks have been drained, and owners are monitoring others until they can be taken out of service for repairs, regulators said.
Environmental advocates, watchdog groups and some citizens say it proves the law is already working, despite officials' urgency to trim it.
'Unfortunately, now that the law was significantly scaled back during the last legislative session, many fewer tanks will need to be inspected,' said Evan Hansen, president of the Morgantown-based Downstream Strategies water consulting firm. 'And the inspections that are still required will likely be done less often.'
The initial inventory mapped 49,000 tanks. Tank owners submitted inspection reports due in January.
Industry groups - notably oil and natural gas - said the law was too burdensome on business. The Legislature and Gov. Earl Ray Tomblin responded this year by removing about 36,000 tanks from the program, saying the law should focus on the most dangerous tanks. More could be exempted if officials decide tanks are sufficiently regulated in other programs.
Those changes take effect in mid-June.
The survey showed some tanks contained thousands of gallons of brine, oil and gas used in natural gas drilling, while one 275,000-gallon tank held hazardous sodium hydroxide, also called caustic soda.
'I do not believe we would've gotten this information had the law not passed,' said Ruth Porter, Department of Environmental Protection aboveground storage tank program director. The information, she said, 'will help us to be able to protect public health and the environment.'
The first round of brief inspection summaries sparked concern: More than 1,500 tanks weren't safe enough to hold chemicals.
Officials contacted owners of about 100 tanks that held hazardous chemicals or sat near public water intakes. About fifty of them said their tanks still held chemicals and were close enough to threaten surface water supplies.
Four tanks held materials threatening enough that federal law deemed them hazardous.
Last year's spill, though, didn't involve a chemical with the 'hazardous' label.
Because the coal-cleaning mixture crude MCHM that leaked into the Elk River last year wasn't considered hazardous, little information was available about how toxic it could be.
Spills of commonplace substances have also convinced officials to turn off the spigot.
In January, a utility closed its water intake after a tanker truck overturned and spilled diesel fuel into a creek. About 12,000 Lewisburg area residents were without running water for at least two days.
After hearing from environmental regulators because of the 2014 law, companies with troublesome tanks said they moved quickly to address problems.
Ten miles upstream from a Mingo County water system serving 1,400 people, CONSOL Energy had two tanks at a coal prep plant holding hazardous caustic soda and sulfuric acid. Several CONSOL tanks have treatment ponds, Porter said.
'Any tanks subject to the rules will be properly placed in containment or removed, as appropriate,' said Cathy St. Clair, CONSOL spokeswoman.
One 275,000-gallon tank at the Eagle Natrium chemical plant in New Martinsville still held caustic soda, but was slated to be out of commission by the end of April, a company spokesman said earlier this month. A small water system serving 300 people sits two miles downstream.
'There was no evidence of any leaking,' said Chip Swearngan, spokesman for Eagle Natrium's parent company, Axiall. 'The site performs daily external inspections.'