DENVER -- Denver International Airport says an electrician working at the airfield drove across a runway without clearance Tuesday, but no aircraft were in the area at the time.

Airport spokesman Chuck Cannon said the runway was not in use at the time but was open and available to air traffic controllers.

DIA officials disclosed the incident on Wednesday and said they had reported it to the Federal Aviation Administration.

Aviation Manager Turner West said the airport tightened its access rules because of the incident.

“Even though there was no danger to any aircraft, we take this type of incident very seriously,” Turner said. “We intend to tighten our procedures and intensify our training to ensure that our airfield is as safe as we can make it.”

He said all crews working near runways and taxiways will now be required to have an escort of specially trained personnel, and fewer workers will be permitted to drive in those areas.