Agent limits get second glance

by Jeff Schmerker
Staff Writer

The U.S. Centers for Disease Control is proposing to impose more
restrictive exposure limits for VX nerve agent, a move local officials
say would have at least minor effects on the Army's chemical weapons
burner in Tooele County.

The update will revise VX exposure limits last set in 1988, said Chris
Bittner, a toxicologist with the state Division of Solid and Hazardous
Waste. The move is made possible due to improvements in testing and the
methodology used to determine safe exposure limits.

The new limit? For general populations, it is 6x10 to the negative sixth
power, or five times more stringent; for worker populations, it is 1x10
to the negative seventh power, or 10 times more stringent.

The new rules would also add an additional 15-minute short-term exposure
sample time, while now there is a five-minute short-term exposure sample
time.

The impetus for the change came about from an August, 2000 meeting
hosted by CDC, according to a report published earlier this month in the
Federal Register. The airborne exposure limit for VX was reevaluated by
using a conventional risk assessment method adopted by the U.S.
Environmental Protection Agency, according to the report.

CDC noted, however, there is no indication the current exposure limits
set by the Army's chemical weapons disposal department "have been less
than fully protective of human health," states the Federal Register
report. "This may be due to rigorous exposure prevention efforts in
recent years as well as the conservative implementation of the existing
limits."

The announcement comes as the Tooele Chemical Weapons Disposal Facility
moves out of its GB agent disposal campaign to a VX disposal campaign.
VX, a colorless, odorless liquid, can kill humans within 15 minutes even
if they come into contact with small doses. A person exposed to the
chemical will at first have difficultly seeing and breathing and have a
runny nose. Headaches follow, then salivation, nausea, giddiness and
anxiety. Lethal doses prompt uncontrolled vomiting, tremors and
defecation, followed by convulsions, coma and suffocation.

The chemical is no longer manufactured in the U.S. but is still stored
at eight stockpile sites. Officials at the Tooele incinerator say VX
will likely be the most difficult of that facility's three chemicals to
dispose of because of its extreme volatility.

Bittner said until the Tooele burner conducts trial burns for VX it will
be difficult to say how well emissions will conform to the proposed
standards. But the facility will have to adjust its agent-detecting
perimeter and facility monitors, he said.

"We probably will need to tweak some things," he said. "We may go back
to them and propose an alternate level."

Changes, if approved, could be enacted within six months or a year, he
said.