WASHINGTON (AP) – Safety officials are warning that the public is at risk of a potentially deadly release of chlorine gas unless the government requires equipment for transporting it.

The U.S. Chemical Safety and Hazard Investigation Board is issuing a safety bulletin today urging sites where rail cars unload chlorine to install automatic shut-off valves and other devices that can stop the flow of gas in an emergency.

The recommendation comes after a safety board survey found that 30 percent of water treatment plants lack the most effective equipment to detect and stop chlorine leaks, leaving the public vulnerable to large-scale releases.

“Chlorine is a very useful but highly toxic substance that needs appropriate safeguards to prevent releases and protect the public,” said safety board member John Bresland.

The U.S. Transportation Department regulates transportation of hazardous material by rail, but its oversight ends once the material begins to be unloaded at a fixed site. Safety board officials are formally recommending that the agency expand its coverage and require companies to install newer emergency shut-off systems.

Transportation Department officials were reviewing the bulletin Wednesday but had no immediate comment.

About 15 million tons of chlorine are produced each year and 3 million tons are shipped by rail across the country. Many water treatment plants that receive the chlorine are in residential communities.

Chlorine railcars currently have excess flow valves designed to stop the flow of chlorine if a valve breaks off while the railcar is in transit. But those valves are not designed to stop leaks during rail car unloading.

One of the worst chlorine accidents in recent years occurred in 2002 in Festus, Mo., when a chlorine rail car transfer hose ruptured and the emergency shutdown system malfunctioned. About 48,000 pounds of chlorine were released during a three-hour period in the community 30 miles south of St. Louis.

The safety board said the Missouri incident is an example of how the newer safety equipment could have prevented a large release of chlorine.

Art Dungan, president of the Chlorine Institute, said the industry supports the recommendation and wants the Transportation Department to establish uniform safety regulations.

“It’s our intent to promote this bulletin very actively to our members,” Dungan said.

Fred Millar, a chemical safety expert at Friends of the Earth, a national environmental group, praised the safety board’s recommendation.

“No individual company has the incentive to spend money on safety equipment and measures if their competitors are not being forced to do the same thing,” Millar said. “I think they’ve done great work in highlighting the need to have what is an absolutely necessary safety device.”

AP-ES-06-13-07 1755EDT