The Army and Marine Corps might not be equipped to respond quickly to crises in Europe or Africa because the services are improperly storing vehicles, weapons and other gear at overseas prepositioning sites, the Pentagon's watchdog agency has warned.

The Defense Department does not have proof that soldiers and Marines properly stored and maintained at least $203.7 million worth of equipment at sites in Italy, Norway, Germany and other locations in Europe, an inspector general report found.

Investigators reviewed five locations where the services pre-stage gear. The stockpiles of tanks, weapons and other vehicles are meant to be used in the event of an emergency, deter adversaries and reassure allies.

But what the inspectors found raised questions about the usefulness of the equipment stored in those locations.

"We believe our findings raise potential concerns regarding the maintenance of prepositioned stock at other U.S. European Command locations that follow the Army Technical Manual 38‑470 and Marine Corps Technical Manual 4790-14/1G," the report states.

Those manuals set the conditions for which humidity levels, maintenance schedules and other steps to protect the equipment are followed. Inspectors found that some vehicles and weapons in the locations went untested or maintained and humidity levels kept at rates that could damage some of the equipment.

The DoD's inspector general's office recommended that:

The Army update its manuals to specify who should control the sites' humidity levels.

The Army clearly state how often weapons stored at the prepositioning sites be maintained.

Troops take the gear out of storage for use in some exercises so it is maintained and used.

The Marine Corps assess corrosion on the equipment it stores in Norwegian caves.

The Marine Corps monitor and control humidity levels.

Marines come up with a process for monitoring maintenance cycles.

The Marine Corps develop a system for maintaining weapons still in the protective packaging used in shipping.

"The Army Materiel Command is committed to Army readiness and ensuring the best-equipped and sustained fighting force in the world," said Lisa Simunaci, a spokeswoman for that command, which oversees the prepositioning sites.

The Army Prepositioned Stocks program requires inspection and maintenance depending on vehicle storage conditions, she added. For vehicles in Europe, that's every 24 months unless they are inside a humidity-controlled environment.

"In that case, they are on a four-year maintenance cycle," Simunaci added. "Small arms and crew-served weapons maintained in either humidity-controlled areas or portable weapon storage vaults, and not removed for training or other reasons, are serviced annually."

The Marine Corps does preventative maintenance checks on its ground equipment in Norway every three years. Operator-level checks are done every two years.

Any equipment used during a contingency or exercise is looked at within 180 days of its return, said Capt. Joseph Butterfield, a Marine spokesman at the Pentagon.

The service also dispatched a team to assess any corrosion on gear stored in Norway in response to the inspector general's report, he said. That work was completed this month, and the findings are forthcoming.

For now, officials at Marine Corps Prepositioning Program-Norway have lowered dehumidifier settings to help mitigate some of the corrosion that inspectors found occurring in the caves, Butterfield said. Those policies will be reviewed and incorporated into future documents to improve the management and maintenance process for prepositioned gear.

"Maintaining relative humidity below 50 percent eliminates the adverse effects of humidity," he said. "Dehumidifiers inside the caves have been set to 46 percent ... and a surveillance program has been established that will monitor dehumidifier settings and humidity levels in the caves."

The Marine Corps is also reviewing its policies on gear stored in packaging materials. Officials plan to update manuals with guidance on proper techniques for that equipment sometime in 2019, Butterfield said.

The Pentagon's inspector general's office requested that any recommendations made in the report that haven't yet been addressed by the services be resolved by Oct. 17.

-- Gina Harkins can be reached at gina.harkins@military.com. Follow her on Twitter at @ginaaharkins.