(The following article by Eric Lipton was posted on the New York Times website on April 24.)
WASHINGTON — At least 225 industrial plants in this country have switched to using less dangerous chemicals since the 2001 terrorist attacks, lowering the risk that people nearby would be injured or killed by toxic plumes, a new study has found.
While these plants represent only a tiny fraction of the estimated 14,000 nationwide that store or use large quantities of extremely hazardous substances, environmentalists nonetheless cite their efforts as proof that companies and utilities can and should make the switch.
“It demonstrates what is possible with a concerted national effort,” said Paul Orum, the author of the report, “Preventing Toxic Terrorism,” which is being published Tuesday by the Center for American Progress, a liberal research and advocacy group.
The plants have often undertaken the changes with little public attention, as happened at Blue Water Pool Chemical. The company, near the airport in Scottsdale, Ariz., no longer uses chlorine gas, which is extremely hazardous, reducing the risk to an estimated 8,300 people.
“I just always had in the back of my mind, what would happen if you had a leak?” said Buddy Andrews, owner of the company. “I just did not want to live with it.”
Congress is debating legislation that may accelerate this process, although there is disagreement over how much pressure should be imposed on plant owners. A bill introduced by Senator Susan Collins, Republican of Maine, would give plant owners the option of replacing chemicals as a way to improve security, while a separate bill introduced by Senator Frank R. Lautenberg, Democrat of New Jersey, would require certain plants to use safer technology if it was considered practical.
The biggest safety improvements have occurred at sewage and water treatment plants. Nationwide, 207 of them have switched to less hazardous processes, most often by replacing chlorine gas with liquid chlorine bleach or ultraviolet light as the primary treatment process.
Chlorine gas is much more dangerous because if a storage tank, often a rail car, is pierced or blown up, the gas could form a cloud that could kill thousands of people. One of the plants that stopped using it, Blue Plains Wastewater Treatment Plant in the District of Columbia, included 1.7 million people in its hazard zone.
An additional 29 manufacturing or electrical power plants also switched chemicals, including Cargill Inc. factories in Memphis and in Eddyville, Iowa, which had used anhydrous sulfur dioxide to soften corn for corn syrup and animal feed. The chemical, which is extremely hazardous, has been replaced by sodium bisulfite, which is a solid and therefore considered much less of a threat.
The study was conducted by contacting 1,800 chemical plants, factories, water utilities and other facilities that had dropped off an Environmental Protection Agency list of industrial facilities that handle significant quantities of extremely hazardous substances. A total of 284 plants either replied to a questionnaire or a follow-up interview about why they were no longer on the list; of those, 225 had made the switch after the terrorist attacks.
Of the plants, 217 said concern over an accidental chemical release had motivated the switch. One hundred and seventeen cited concern over terrorism or a desire to improve security. The cost of changing varied widely, from less than $100,000 to more than $20 million. Several plant managers said in interviews on Monday that the new approaches had also resulted in higher operating costs.
The total population put at risk by all 284 plants, according to E.P.A. data, was about 38 million, the report said.
That number overstates the extent of the actual risk, because it assumes that a major accident would discharge the toxic chemical in a circle around the plant, when in reality chemical leaks generally form much narrower plumes driven by wind and other factors, said Richard A. Falkenrath, a former deputy homeland security adviser at the White House.