A small amount of chemical vapor was detected Thursday in an M55 rocket storage igloo at the Pine Bluff Arsenal, officials said.

The vapor from the rockets, which contain a nerve agent, was contained in the igloo, according to a news release from the arsenal. "At no time did it pose a threat to Arsenal employees or the local community," the release said.

Carole Newton, an arsenal spokesman, said that employees were working to isolate the leaking rocket. It will be removed and stored in an igloo with 42 other rockets that have leaked, she said.

In the past, it was common to discover one or two leaking rockets a year at the arsenal. But before Thursday, the last occurrence of such a leak was on Jan. 14, 2002, Newton said.

An arsenal incinerator which began operating in March has disposed of 13,330 rockets and nearly 120,000 pounds of the nerve agent sarin that was drained from them. The arsenal once housed more than 90,000 agent-filled rockets.

The incinerator experienced delays after a number of unexpected fires here and at a similar incinerator in Oregon this spring.

This story was published Friday, July 29, 2005.