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Use of Chlorine Gas at Wastewater Plants Questioned
By Benton Ives-Halperin, CQ Staff
With lawmakers preparing to introduce chemical security
legislation, environmental groups have renewed calls for wastewater treatment
plants to abandon the use of chlorine gas — which can produce a lethal cloud if
released — as a disinfectant.
At least 15 plants, many in populous areas, have stopped using the gas since
1999.
“It is essential that Congress now enact new safety standards that require the
conversion of dangerous technologies to safer chemicals or processes wherever
alternatives exist,” wrote Rick Hind, director of the Greenpeace toxics
campaign, in a September letter to Senate Homeland Security and Governmental
Affairs Chairwoman Susan Collins, R-Maine.
But the chlorine industry says security guidelines — developed with the
Environmental Protection Agency and security experts — recommend that each water
utility make its own decision on whether to use chlorine gas or a substitute.
“There’s not a one-size-fits-all [solution],” C.T. “Kip” Howlett Jr., executive
director of the Chlorine Chemistry Council, said in a telephone interview. “In
those guidelines there’s not a recommendation to deselect chlorine.”
Environmentalists say rail containers hauling chlorine gas and treatment plants
make tempting terrorist targets: One worst-case scenario analysis by the Naval
Research Laboratory found that a ruptured rail car near downtown Washington
could produce a gas cloud capable of killing up to 100,000 people, at a rate of
100 per second.
“It’s outrageous that [chlorine gas] is being used in urban areas,” Carol
Andress, an economic development specialist at Environmental Defense, said in a
telephone interview. “There are readily available, affordable, safer
alternatives to chlorine gas” being used at wastewater plants, she said.
Many wastewater treatment facilities use chlorine gas to disinfect contaminated
water before discharging the treated effluent into local waterways. But
environmentalists argue treatment plants should substitute sodium hypochlorite —
liquid chlorine about three times stronger than household bleach — for chlorine
gas.
For its part, the wastewater treatment industry says chlorine gas is a major
security priority for municipalities. But the industry also says other factors —
such as efficacy of disinfecting agent, cost of new systems and time to install
new equipment — all play a role in the selection of a treatment option.
“There is a place in this world for chlorine gas; it’s not going to go away,”
Chris Hornback, director of regulatory affairs for the National Association of
Clean Water Agencies (NACWA), said by telephone. “There are certainly security
considerations for some communities that ultimately may dictate that they get
rid of chlorine gas.”
The Department of Homeland Security (DHS) and NACWA are working jointly on a
tool that would allow municipalities to evaluate alternatives to chlorine gas.
“It’s not telling them that they have to switch, it’s not making it any cheaper,
it’s giving them a quick tool to evaluate some alternatives,” Hornback said.
Moving Away From Chlorine Gas
According to a 2003 report produced by Environmental Defense, 62 wastewater
treatment facilities reported in 1999 that a major chemical release at their
plant could affect 100,000 people or more. At the time the report was released,
12 of those plants had stopped using chlorine gas.
Since that time, three more plants in Portland, Ore., Baltimore, and Niagara
Falls, N.Y., have switched to liquid chlorine treatment operations, according to
Andress.
One of the facilities that no longer uses chlorine gas is the Blue Plains Sewage
Treatment Facility in Washington, which accelerated plans to replace the gas
with sodium hypochlorite in the aftermath of the Sept. 11 attacks. The switch
cost Blue Plains customers about 25 to 50 cents more per monthly bill, according
to environmentalists.
Treatment by ultraviolet (UV) light — which disinfects water by destroying
microorganisms — is another alternative to chlorine gas. Currently, four of the
62 facilities identified by Environmental Defense use UV treatment systems.
But the wastewater industry says other factors contributed to District
officials’ decision to quit using chlorine gas at Blue Plains.
“It is my understanding that [the D.C. Water and Sewer Authority] did not make
the decision in a vacuum,” said Hornback. “The increase in costs was not that
significant and the decrease in risk and hazard was by far worth the
investment.”
Many Uses for Chlorine
Chlorine is used for more than just wastewater treatment. About 40 percent of
chlorine manufactured in the United States is used to make plastic, specifically
vinyl used in products such as piping and flooring. Moreover, the industry says
that chlorine would be the cleansing agent of choice in the event of a bioterror
attack.
“If you’ve got a bioterror attack, chlorine, in whatever form — gas, liquid,
solid — is going to be [the] first line of defense,” said Howlett, noting that
chlorine was used to disinfect the Hart Senate Office Building after anthrax was
found there in 2001.
And although environmentalists malign chlorine gas for its toxicity, the
industry notes that chlorine plays a key role in purifying drinking water.
“You never have pure black-and-white decisions about any of these things,”
Howlett said.
Benton Ives-Halperin can be reached at bihalperin@cq.com.
Source: CQ Homeland Security