Workers at the Pine Bluff Arsenal have identified the leaking M55 rocket that released a small amount of sarin vapor inside a rocket storage igloo, officials said Friday.

Laboratory tests confirmed the presence of the sarin inside the igloo July 28. The vapor was contained in the igloo, according to an arsenal news release.

Sarin is a colorless, tasteless liquid chemical warfare agent that can evaporate into a gas, according to the federal Centers for Disease Control and Prevention. It is classified as a nerve agent, the most toxic and rapid acting of the known chemical warfare agents. It originally was developed in Germany in 1938 as a pesticide.

On Thursday, arsenal workers identified the leaking rocket and placed it in a sealed steel container, according to the release. The container will be moved to a separate igloo for storage, said Carole Newton, an arsenal spokesman.

"At no time did the leak pose a threat to the arsenal employees or the local community," the release said.

As of last week, the arsenal incinerator, which began operating in March, had disposed of 13,330 rockets and nearly 120,000 pounds of sarin that was drained from them. Newton did not have the latest disposal numbers late Friday. The arsenal once housed more than 90,000 rockets containing chemical-warfare agents.

This story was published Saturday, August 6, 2005.