The Department of Defense needs to do a better job handling hazardous materials, says the Government Accountability Office.

Hazmat shipments have been improperly documented and packaged, leading to delays and risks to safety and national security, the watchdog agency found.

Part of the problem is that hazmat shipping is governed by a complex web of laws and regulations administered by different civilian and military agencies, GAO said.

At least 44 times over a two-year period, the Defense Department did not provide hazmat carriers access to secure areas where they could hold shipments of arms, ammunition or explosives.

It was an infrequent occurrence – there were more than 70,000 such shipments during that period – but even that small percentage creates a risk to safety and security, GAO said.

Another challenge is that the Federal Motor Carrier Safety Administration’s safety enforcement data system is not reliable, GAO said.

The agency referenced a report it posted last February saying that the CSA safety enforcement system has data shortcomings that limit its usefulness as a predictor of crash risk.The agency also noted that FMCSA disagreed with and challenged this assessment.

GAO recommended that the Defense Department find out what is causing the improper documentation and packaging. The department also should make sure that all its facilities provide secure holding areas for sensitive shipments, and should see if it needs to make any changes in the way it determines carrier eligibility.