Two people were killed in a head-on two-vehicle collision Monday in Buckingham County on U.S. Route 15 near Willis Mountain Plant Lane.

Both Deborah A. Stearnes, 49, of Dillwyn, and Thomas C. Mason Jr., 61, of Disputanta, died at the scene, according to Virginia State Police spokeswoman Corinne Geller.

Stearnes was not wearing a seatbelt, Geller said, while Mason was wearing a seatbelt.

“A 2005 Pontiac Grand Am was traveling south on Route 15 when it crossed the centerline and struck head-on a northbound dump truck,” Geller said. “Despite the dump truck driver’s attempts to avoid the oncoming Pontiac, the two vehicles collided and the dump truck ran off the left side of the highway, went through a guardrail, overturned and struck a tree.”

Stearnes was driving the Pontiac while Mason was driving the dump truck.

Geller said Trooper C.L. Foster is investigating the crash, reported at 9:45 a.m. Monday.

Geller said the cause of the crash remains under investigation. “Alcohol was not a factor in the crash,” she said.

U.S. Route 15 was closed in both directions for most of the day Monday.