INSTITUTE, W.Va. (AP) - Almost three months after tainted tap water became part of 300,000 West Virginians' daily lives, independent scientists reviewed lab rat studies and hospital reports to reassure residents their water is safe, even if it still contains trace chemicals.
"We're willing to use the word safe, and say so emphatically," Jeffrey Rosen, a Massachusetts scientist and research co-leader, said Tuesday at West Virginia State University.
On Tuesday, the scientists discussed the federal drinking water standards for safe levels of some little-known chemicals that spilled into the water system Jan. 9. The scientists offered their own standards, eight times more conservative than federal officials in calling the water safe.
The chief concerns have centered on a chemical called crude MCHM, which is used to clean coal.
Local health officials, meanwhile, are growing frustrated waiting for information and guidance to judge the chemical's long-term effects.
Centers for Disease Control and Protection officials are still reviewing January hospital reports from patients with ailments possibly linked to chemical contact, from rashes to nausea. The information could be crucial to track how the population's health changes over several years, said Dr. Rahul Gupta, health officer for Kanawha County.
The medical monitoring program is included in a bill Gov. Earl Ray Tomblin signed Tuesday. The new law also toughens regulations on aboveground storage tanks and public water systems.
Gupta said quick action is crucial, since people generally start forgetting daily habits about how much water they drank 90 days afterward. The January leak from Freedom Industries in Charleston spurred a tap water-ban across nine counties for four to 10 days.
"The (Centers for Disease Control and Prevention) should not be taking this long," Gupta said. "I think it should be a given that some sort of preliminary draft report should be out by now."
On Tuesday, the water company contaminated by the spill started to fix a source of trace chemicals that are still getting into people's homes.
The company said chemicals at levels 2,000 times lower than what's been deemed safe to drink have been detaching from the filters at the company's water treatment plant and circulating into people's taps. West Virginia American Water began replacing the 16 filters, which will cost more than $1 million and may take eight weeks or longer, spokeswoman Laura Jordan said.
Gupta pointed out that no one has yet established a long-term safe drinking level for the chemicals in question. The CDC's level, quickly drawn up with limited animal research, was intended to be a short-term safety guideline. But the agency's definition of "short-term" isn't clear.
Even the independent scientists' benchmark only counted on people being exposed to the chemical for 28 days.
The scientists considered consuming, bathing in and breathing in the chemical in tap water, while the federal standard only accounted for drinking it. The researchers also addressed possible kidney and liver damage as well as anemia.
Dr. Michael Dourson, a Cincinnati toxicologist with the group, said the chemicals don't spark mutations, one cause of cancer. The researchers used a computer program to determine if the chemicals structurally resembled other known mutagens, he said.
A long-term safety level could be established over five years, Dourson said, but more data would be needed, like the 533 local hospital visits under review by the CDC. Researchers would tell people the safe level is lower over a longer time, he said.
Residents have remained concerned about the quality of the water supply and have been slow to regain confidence in the officials tasked with protecting it.
The governor reacted to public outcry by shuffling $762,000 in state money toward a larger research project, which included sampling in 10 homes, smell tests, a review of previous research and Tuesday's critiques of the safe drinking level.