In a letter dated March 1, the U.S. Environmental Protection Agency asked the Army´s Anniston Chemical Agent Disposal Facility for additional data. The chemical weapons site destroys weapons, including M55 rockets with capacitors containing PCBs.

In June 2002, the EPA issued the Army a Toxic Substances Control Act permit that requires the furnace system to destroy 99.9999 percent of PCBs.

During test burns last year, samples collected at the furnace exhaust duct met the standard, but test results at the facility´s common smokestack failed to meet the standard by a small margin for three of the four test burns, according to the Army. The common smokestack was venting emissions from the furnace destroying the M55 rockets as well as a liquid incinerator, the Army said.

The Army says the results from the duct samples should prove the furnace is in compliance.

"The trial burn results from the [deactivation furnace system] duct demonstrated compliance with TSCA requirements," said Timothy K. Garrett, site project manager for the Anniston chemical weapons facility. "However, at EPA´s request, we will perform these additional tests. Protecting human health and the environment is our top priority."

The smokestack emissions, while slightly higher than expected, were below levels thought to impact health, according to the Army.

Since August, the Army´s Anniston site has destroyed more than 19,000 M55 rockets that contain sarin nerve agent, and more than 21,000 gallons of liquid sarin.

The weapons are aging Cold War munitions that the Army is destroying.