MCHM screening level weak, WVTAP says
A team of experts has concluded that the “screening level” set by the U.S. Centers for Disease Control and Prevention — and used by state officials to declare drinking water safe after January’s chemical leak — was too weak, because it didn’t consider the risks of inhaling fumes of the Crude MCHM that contaminated 300,000 homes across a nine-county region.
The five-person panel chosen by the West Virginia Testing Assessment Project also recommended that the level should have been more set at a lower concentration to ensure it was protective of sensitive populations, specifically formula-fed infants.
The WVTAP panel concluded the appropriate screening level should have been 120 parts per billion of MCHM, which is more than eight times more stringent than the 1-part-per-million emergency number set by the CDC in the hours after the leak. One part per million is equal to 1,000 parts per billion.
The new WVTAP screening level is well above the MCHM concentrations the group found in a sampling of tap water from 10 homes around the region, conducted in mid-February, and also well above the levels more recent sampling by the water company found in water being distributed by its Elk River plan. The new screening level is less protective than the 10 parts per billion concentration that Gov. Earl Ray Tomblin set as a goal for the region’s water system at a time when state sampling was not quantifying detections of MCHM below that level.
The WVTAP number, though, is based on an average exposure of 120 parts per billion over a 28-day period. The CDC called its screening level a “short-term” number, but never said publicly what period of time it considered that to be.
WVTAP experts conceded they are not able to say for sure whether exposures in the 28-day period immediately following the Jan. 9 leak — when MCHM concentrations were likely the highest — were above or below that 120-ppb number, because they don’t have in-home testing data to determine an average exposure over that period of time. The new WVTAP number also does not tell residents what level of MCHM is safe over a longer period of time, such as the nearly three months since the leak, or in the months to come.
“The fact of the matter is that there is very little data available about what levels people were actually exposed to,” said Andrew Whelton, a University of South Alabama environmental engineer and one of the leaders of the WVTAP. “What is the exposure then, and what is the exposure now?”
New data from West Virginia American Water has shown that low levels, from 0.42 parts per billion to 0.60 parts per billion, of MCHM are being funneled into the water system from the Elk River water distribution plant’s carbon filters, which captured some of the material from the leak.
But little testing of tap water from homes — where Whelton has theorized some of the chemical was trapped in plumbing system materials — has been done. The Tomblin administration has not yet decided if it will fund a larger effort to test more than 600 more homes to get a better sampling of regional drinking water contamination levels.
WVTAP officials held a public meeting and news conference Tuesday to discuss the health-effects panel’s preliminary findings, following a day-long, closed-door meeting of the expert panel, which included members from Florida, Minnesota, Israel and the United Kingdom.
The panel was organized by a Cincinnati-based consulting firm, Toxicology Excellence for Risk Assessment. The firm frequently does work for chemical companies and industry trade groups. WVTAP officials said a complete “conflict of interest” disclosure listing TERA’s industry ties would be made public with its final report in May.
Tomblin appointed the WVTAP team last month, under public pressure over lingering and potentially long-term impacts of the leak from the Freedom Industries tank farm, located just 1.5 miles upstream from West Virginia American’s intake serving 300,000 residents across a nine-county region.
Among the WVTAP’s duties was to examine the 1-ppm screening level that CDC officials devised. State officials and the water company pointed to that concentration as proof that the flushing of the water distribution system had made it safe to remove a broad do-not-use order issued following the chemical leak at Freedom Industries on Jan. 9.
Outside public health and toxicology experts have said the CDC moved too quickly and had inadequate data to make such a declaration, while the CDC has defended its number as conservative and protective of the public.
Michael Dourson, president of TERA, said the expert panel was able to improve upon CDC’s work because members had access to new information about MCHM that the CDC did not have. For example, Dourson said, reports of residents experiencing adverse health effects from MCHM fumes in the air led the expert panel to include inhalation risks in its calculations, something the CDC didn’t to.
“We had more information than the Centers for Disease Control, so we were able to use that information,” Dourson said.
But a chemical data sheet from Eastman Chemical, the makers of MCHM, clearly warned that “At elevated temperatures, vapor may cause irritation of eyes and respiratory tract.” That data sheet was available the night of the Jan. 9 leak and was used by the CDC when it first developed its screening level.
During the WVTAP event Tuesday, Dourson emphasized that the levels of chemicals involved were very small. He compared them to one-tenth of the contents of a small packet of sugar. WVTAP co-leader Jeffrey Rosen, president of the consulting firm Corona Environmental, compared a part per billion to a drop in a swimming pool.
Rosen added that he understands residents remain concerned, and that they have every right to be concerned.
“You have been through something that should not have happened,” Rosen said. “You have a chemical in your water that should not be there.”
Rosen emphasized, though, that even the highest levels of MCHM found by the WVTAP’s limited home testing — 6.1 parts per billion — were well below the new 120-ppb screening level for a 28-day exposure. Dourson said that screening level for longer exposures could be calculated, and would be end up lower than 120 parts per billion.
In a prepared statement, state Department of Health and Human Resources Secretary Karen Bowling said the WVTAP panel’s 120-ppb number was “clearly an affirmation that our water is safe and the CDC’s calculation at the time of the incident was appropriate.”
But Richard Denison, a toxic chemicals expert with the Environmental Defense Fund, said the WVTAP findings don’t answer all of the questions about potential impacts of the MCHM leak.
“What you really have to do is calculate the exposure from day one of the event,” Denison said. “Unless they found some new data ... it’s hard to see how they would overcome all of these sources of uncertainty. We’re now approaching three months and the chemical is still being detected, albeit at low levels. That says this is persisting in the water system in a way that wouldn’t have been expected given their rosy statements.”
Reach Ken Ward Jr. at firstname.lastname@example.org or 304-348-1702.