Furnaces at the Pine Bluff Arsenal resumed burning chemical weapons early Tuesday morning after a small fire shut down operations for nearly two days.

"We started incineration a little after 2 a.m. today," arsenal spokesman Raini Wright said in an e-mail message Tuesday. "Operations are progressing smoothly."

The shutdown came after a fire broke out in an explosion containment room Sunday morning.

That fire was put out within 20 seconds, and 35 rockets filled with nerve agent that were already in line to be processed were sent through the incinerators.

However, the furnaces were then shut off to give crews time to investigate what caused the blaze. The cause had yet to be determined as of Tuesday afternoon, Wright said.

The fire began when a rocket that had been packed with GB nerve agent ignited as it was being cut into pieces to be more easily incinerated. No nerve agent escaped from the airtight containment room.

Sunday’s fire marked the third time in two weeks that incineration operations have stopped at the Jefferson County arsenal.

A similar fire May 11 stopped work for two days. Last week, operations shut down again because of concerns over a fire that broke out at a similar facility in Umatilla, Ore.

The Pine Bluff Arsenal houses 12 percent of the nation’s chemical weapons stockpile. Workers there are hoping to destroy the rockets and ton containers full of nerve and blister agents in accordance with an international treaty for nations to get rid of their chemical weapons by 2012.