CHARLESTON, W.Va. -- Tomblin administration officials continued on Monday to decline to provide detailed answers why they think 1 part per million of Crude MCHM is safe for West Virginians to drink.
Federal agencies also refused to explain how they calculated that figure in the absence of any real regulatory guidelines or published health standards for the material, also known as 4-methylcyclohexanemethanol.
A Ph.D. chemist who works with the Environmental Defense Fund wrote on his organization's blog that West Virginia officials are trusting "shaky science" in their "rush to restore water service" to 300,000 residents in a nine-county region.
Richard Denison wrote that officials "made significant leaps in their calculation of a 'safe' exposure level -- including assumptions that deviate from generally accepted practices."
"As a result, these estimates fail to adequately account for either acute or chronic effects from ongoing exposure to water contaminated at the 1 ppm level," Denison wrote. "At a bare minimum, the public deserves to know a lot more about the calculations behind officials' insistence that a 1 ppm level in drinking water is safe."
Tomblin administration officials have emphasized that water samples in the last two days have begun to more consistently show far less than 1 part per million of MCHM in drinking water from West Virginia American Water's Elk River treatment plan. Some samples, they note, are coming back with none of the chemical at all being detected.
"The numbers we have today look good," Tomblin said at a noon briefing Monday.
Top Tomblin aides continue to point to the U.S. Centers for Disease Control and Prevention, which, along with the federal Agency for Toxic Substances and Disease Control, came up with the figure 1 part per million.
When asked for more information about where the number came from, Department of Health and Human Resources Secretary Karen Bowling pointed to the "material safety data sheet," or MSDS, from Eastman, the maker of the chemical that leaked.
Bowling, though, downplayed the fact that there is precious little toxicological data and few -- if any -- public and peer-reviewed studies of what the chemical would do to humans if ingested.
"It's like any chemical that's out there," Bowling said. "There are many chemicals of which we don't have all the information. There's been no indication that what we're doing is improper."
State officials have told the Gazette to ask the CDC for more information. But on Monday, the CDC referred questions to West Virginia American Water.
Late last week, Dr. Letitia Tierney, commissioner for DHHR's Bureau for Public Health, said that the state's announced limit was based on a paper from 1990 by Eastman that was never published in publicly available journals.
That study, she said, was the basis for the median lethal dose, or LD50, listed on an Eastman MSDS that's been circulated by local emergency responders, health officials and the media.
On that MSDS, the LD50 for Crude MCHM is listed as 825 milligrams per kilogram. This means that when tested on rats an 825 milligram dose per kilogram of body weight was enough to kill half the rats.
Here's how Tierney said CDC experts took that LD50 and came up with the 1-part-per-million figure that West Virginia officials are now citing as a safe level in local water: