Chlorine Gas Poses Health Threat To More Than 19 Million People

December 3, 2003

(3 December 2003 — Washington, D.C.)  A study released today by Environmental Defense and a coalition of environmental groups finds that 19 million people are at risk from a major release of deadly chlorine gas from their local sewage treatment plant.  The report, Eliminating Hometown Hazards, used public information to determine that 45 sewage plants continue to use chlorine gas in heavily populated areas.  A major incident, accidental or deliberate, at any one of these plants could kill or seriously injure any of more than 100,000 people.  The study and a complete list of the 45 facilities are available at

“All facilities using large amounts of dangerous chemicals have a public responsibility to reduce the hazards they pose,” said Environmental Defense analyst Carol Andress.  “For wastewater treatment there is no excuse for using chlorine gas.  Safer alternatives are available, affordable and practical for facilities large and small.  If they’re not willing to protect the public from such a preventable hazard, they shouldn’t receive public money.”

Six facilities — Back River Wastewater Treatment Facility in Baltimore, Metro Wastewater Reclamation District in Denver, Detroit Wastewater Treatment Plant in Detroit, Secondary Wastewater Treatment Plant in Modesto, City of Niagara Falls Wastewater Treatment Plant in Niagara Falls, and Central Valley Water Reclamation in Salt Lake City — have reported that they could each seriously injure any of more than one million people.  Environmental Defense found that the Denver and Baltimore plants plan to use safer alternatives, but the other plants reported no such intention.  In total, more than 1,300 wastewater treatment facilities reported using chlorine gas in 1999, the most recent year that comprehensive data is available.  The report’s findings are based on public data as well as direct efforts to correspond with the largest plants. 

Among the report’s recommendations:

  • End public funds for dangerous facilities.  Millions of public dollars are spent each year to help build or improve wastewater treatment facilities.  Congressional, state and EPA officials should ensure that, allowing time for transition, taxpayer money is not spent at facilities that pose an unnecessary risk.
  • Maintain public access to chemical risks.  Public access to information about the potential consequences of a chemical release is one of the most effective tools for motivating risk reduction.  Public scrutiny of sewage plant practices has motivated many facilities to choose safer alternatives.  Access to information is already restricted, yet some in Congress want to eliminate even that. 
  • Set federal standards for reducing hazards.  More than two years after 9-11, there are no federal requirements that require facilities using dangerous chemicals to employ the best possible industry practices to reduce hazards.  The Chemical Security Act of 2003 would require safer practices but has stalled in Congress where it has met opposition from the chemical industry.