RALEIGH, N.C. — Mowing at all national parks has been suspended indefinitely because of safety concerns after a maintenance worker cutting grass along the Blue Ridge Parkway in North Carolina fell to his death.

The National Park Service sent an order to its regional offices Friday to halt mowing at its 397 parks that are spread across every state except Delaware.

The agency is reviewing safety procedures after 63-year-old Dana Bruce of Alexander died at the Haw Creek Overlook north of Asheville. The seasonal worker’s riding mower fell more than 140 feet down a boulder-strewn embankment May 7. He was pronounced dead at the scene.

“We take all accidents seriously and use them as an opportunity to learn so that this kind of accident does not happen again,” park spokesman Jeffery G. Olson wrote in an email.

Bruce was an Army medic who served in Vietnam and was working his third summer for the park service. He was trimming a 12- to 15-feet-wide area between a wooden guardrail and a cliff when he lost control of the zero-turn riding lawnmower and went over the edge, said Steve Stinnett, chief ranger for the Blue Ridge Parkway.

Federal Occupational Safety and Health Administration investigators are reviewing the accident, but did not return messages left by the Associated Press. A five-member National Park Service accident investigation team concluded its investigation Monday, but has not released its findings. Stinnett said it would be “months” before the results of that report are made public.

It is unclear how long the grass will grow unchecked nationwide. Olson said each park has a safety review checklist to complete before mowing can resume. The duration of the suspension will depend on the size of the park, the amount of equipment and the number of employees.

“Small parks with little to mow, few pieces of equipment to check, and few personnel to go through safety briefing and training will be back mowing in a matter of hours,” Olson wrote.

Larger parks could go without mowing for weeks.

“We will complete the safety self-certification process in the time required and ask park visitors for their patience if the grass gets a little long until we get back to mowing operation,” Olson wrote.