The Pine Bluff Arsenal tightened security Wednesday after three people entered a restricted area where chemical weapons are stored, officials said.

“At this time, we do not know exactly what happened,” said spokesman Cheryl Avery, adding that the breach is being investigated. The breach took place just before midnight Tuesday in the Bond Road Exclusion Area, a 500-acre area in the northern part of the arsenal where chemical weapons are stored.

“We know the stockpile has not been compromised,” Avery said, referring to the weapons. She was not aware of any damage to arsenal facilities.

Despite a search of arsenal grounds, the three people were not identified or apprehended. For security reasons, Avery would not disclose whether the security guard who spotted the three was able to provide physical descriptions.

Avery also did not disclose whether the area abuts private property.

She said the entire area is fenced and that access is restricted to authorized personnel. She could not recall a previous breach in the area.

Because of the enhanced security measures, all vehicles entering and leaving the arsenal were being searched well into the morning Wednesday.

“We have a highly trained security force,” Avery said. “We want to assure the community that safety is our primary concern, and we’re doing everything possible to maintain that commitment.”

State and local officials, as well as the congressional delegation, were notified of the breach early Wednesday morning, Avery said.

Arkansas State Police were informed about the breach, spokesman Bill Sadler confirmed. He said the department did not respond because the breach occurred on federal property.

The arsenal, one of eight sites where the nation stores its chemical weapons, holds 12 percent of the United States’ chemical weapons stockpile. Incineration of chemical weapons, which began March 29, is on hold until May because of a maintenance project.

For decades, weapons containing nerve gas and chemical agents such as mustard gas have been stored in underground igloos at the arsenal. The United States is working to destroy its national stockpile by 2012 to comply with an international treaty.

This story was published Thursday, January 26, 2006.