A Pennsylvania cyclist died after being struck by a commercial trucker while competing in a triathlon in Ohio, authorities said.

Kristen Oswald, 44, of Royersford, died early Sunday after she ventured outside an established safety zone for bicyclists on a highway in Delaware County as part of the Ironman 70.3 Ohio Triathlon, Ohio State Highway Patrol officials said.

Oswald, who was wearing a helmet at the time, was pronounced dead at the scene after being hit by a white tractor-trailer driven by Claude Tremblay, a 55-year-old Canadian man from Sarnia, Ontario, authorities said.

Tremblay was not charged and neither alcohol nor drugs were expected to be a factor in the crash, Lt. Robert Sellers said.

“We don’t know why yet, but the bicycle traveled outside of the safety zone and into traffic,” Sellers told ABC News. “The driver stopped right after the accident. We did conduct a Department of Transportation inspection as well. But he does not appear to be at fault in any way.”

The fatal wreck closed westbound lanes along US 23 for roughly three hours and sent race officials scrambling to track down Oswald’s husband, who also took part in the competition, Sellers confirmed to The Post.

Triathlon officials said in a statement obtained by WBNS that the accident occurred shortly after the bike portion of the race.

“Our condolences go out to the athlete’s family and friends, who we will continue to support,” race officials told the station. “We are continuing to work with local and state authorities to gather all the details of how this incident occurred and will assist them in any way possible.”

Attempts to reach Oswald’s husband were unsuccessful on Monday.

More than 2,500 people were registered to compete in the triathlon, the Delaware Gazette reported.