"In day-to-day toxicology," Scharman said, "that's not very helpful."
Based on her research so far, Scharman said that even though residents could have consumed the water for hours before the "do not use" order was issued, the short-term, acute impacts are of greater concern than any long-term effects -- assuming residents don't go back to their taps before they're told it's safe to do so.
Along with the vacuum of health-effect information, Scharman noted, there's been some confusion about exactly what substance was involved.
For one thing, 4-methylcyclohexanemethanol has quite a few synonyms. For another, because there's so little known about it, searches of online databases can easily pull up a different substance, leading to misunderstandings about the potential health impacts.
Some residents -- and some news outlets -- have cited health information about chemicals other than those that were actually involved in the Freedom Industries leak.
Also, during a news conference Friday morning, West Virginia American Water President Jeff McIntyre revealed that his company initially was given incorrect information -- he didn't know by whom -- about what material was involved in the spill.
McIntyre said his company thought the treatment systems at its Elk River facility would be adequate for the chemical that it was initially told had leaked. Crews later figured out that wasn't the case, especially after treated supplies at the plant had a "licorice" smell -- the same that nearby residents complained of earlier in the day.
Now, West Virginia American says it's left with no treatment options. The company says it only can try to clear the contaminant by physically flushing its many miles of service lines.
"Unfortunately, this is in the distribution system," McIntyre told reporters. "Once it's in the system, there is no treatment for it."
While residents depend on regulators and the water company to ensure their drinking water is safe, federal and state laws set limits and mandate sampling for only certain chemicals, and 4-methylcyclohexanemethanol is certainly not among them.
McIntyre said his company began trying to test for the substance only after it learned about the leak. He said the substance was detected, but that West Virginia American was not able to quantify the concentrations. Even if it had, he said, the company had no regulatory or public-health guidelines to judge if the detected levels were safe.
Later, during a Friday afternoon news conference, National Guard Gen. James Hoyer said the federal Centers for Disease Control had advised that 1.0 parts per million would be an acceptable level for drinking water. Hoyer said the CDC told state officials the chemical concentration would have to get below 0.1 parts per million for residents to not notice the smell or color changes.
It was not clear Friday how those figures were developed by the CDC, but the tests had shown the chemical levels dropped from 2.0 parts per million to 1.7 parts per million, Hoyer said.
The lack of health guidelines or regulatory limits isn't that unusual, either. Few chemicals are actually regulated by safe-drinking-water or other water-quality rules, and the U.S. Environmental Protection Agency has tested only about 200 of the 84,000 chemicals in the agency's inventory.
"Most chemicals in commerce we know very little about," said Celeste Monforton, a George Washington University public-health researcher. "This stuff is in the water now, and people have ingested it, and we just don't know. It's very concerning."
Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.