More than 100 chemical plants throughout the United States -- including 12 in the Los Angeles Basin -- each could expose millions of people to dangerous concentrations of toxic gas in the event of a terrorist attack or major accident, according to industry documents filed with the U.S. Environmental Protection Agency.
In Southern California, eight plants in Los Angeles County, three in San Bernardino County and one in Riverside County are each capable of exposing a million or more people to the gases, and some people could receive doses high enough to cause death or serious injury, the documents show. About 30 other plants in the region handle smaller volumes of chemicals that could affect between 100,000 and 1 million people.
Residential neighborhoods, child-care centers, schools, amusement parks, hospitals and convalescent homes all lie within the areas in which people could be killed or injured by the gases, according to the reports that chemical companies are required to file with the EPA.
In the Los Angeles region, companies and municipal facilities that pose the greatest risk handle chlorine, which they use mostly to make cleaning solvents and disinfect drinking water. At high concentrations, chlorine is deadly when inhaled.
High-ranking officials in the Bush administration have warned that U.S. chemical plants are highly vulnerable to terrorism.
The danger of an attack "is both real and credible," Assistant Atty. Gen. Paul Corts wrote last month to the General Accounting Office, the investigative arm of Congress. The GAO concluded in a March 14 report that "chemical facilities may be attractive targets for terrorists intent on causing economic harm and loss of life."
"To date, no one has comprehensively assessed the security of chemical facilities," the GAO report says. "Despite the industry's voluntary efforts, the extent of security preparedness at U.S. chemical facilities is unknown."
By law, chemical companies are not required to take safeguards to reduce the likelihood of an attack or sabotage, and no current law explicitly gives federal officials the authority to conduct inspections or mandate security measures.
Despite those concerns, Congress and the Bush administration, after a year and a half of debate, have been unable to agree on legislation that would require security measures at chemical plants.
About 15,000 plants nationwide, including about 1,000 in California, are required under the Clean Air Act to detail their worst-case scenarios in reports to the EPA.
Industry representatives say those scenarios are highly unlikely, even in a terrorist attack, because they assume that all safety equipment such as sensors and shut-down valves would fail and no one would try to escape the odorous chlorine fumes.
"It grossly overstates and misrepresents what is likely to happen," said Kit Howlett, executive director of the Chlorine Chemistry Council, an industry group. "There has not been a single fatality [involving chlorine] off-site in the 70 years we have been keeping these records."
The area that faces the most risk surrounds Santa Fe Springs, where three chemical plants handle 90-ton rail cars containing chlorine. Under the worst-case scenarios described in the documents filed with the EPA, the entire contents of a rail car would be released within 10 minutes and toxic concentrations of chlorine gas could then spread 14 miles.
In the immediate area, the gas would be deadly. Farther away, people would breathe levels known to cause chest pain, shortness of breath, vomiting, coughing, toxic pneumonitis and swelling of the lungs. As far as 14 miles away, the gas could cause mild irritation of the respiratory system.
Another serious risk involves a plant in Torrance, which is within one-tenth of a mile of two child-care centers. As many as 8 million people live within the area that would be exposed in a worst-case release at that plant. And even a small accident -- releasing eight pounds of chlorine -- could expose the child-care centers, two convalescent homes and roughly 2,700 residents, according to the plant's report.
Company officials in the Los Angeles region declined to comment on any security issues. Some managers say publishing the worst-case data is like painting a bull's-eye on their plants for terrorists.
EPA officials, however, say there are benefits to public awareness. Daniel Meer, a Superfund branch chief at EPA's regional headquarters in San Francisco, said the reports pressure companies to seek safer compounds and alert communities to risks at plants that, in many cases, look innocuous.
Chlorine is also a potential hazard at municipal water-treatment plants, including several operated by the Metropolitan Water District of Southern California. The MWD says it has stepped up security at all of its facilities since Sept. 11, 2001.