MOUNT VERNON — A van struck the north side of the U.S. Post Office around 9:35 a.m. today in downtown Mount Vernon, breaking windows and damaging a brick wall.

The vehicle narrowly missed U.S. Postal Service worker Jeff Chester as he sorted mail into boxes just inside the building, said Postmaster D.R. Monty. Most of the broken window glass fell on the exterior side of the wall.

“I was working in my office back there, and I heard kaboom,” Monty said.

The Post Office remained open after the incident, though one corridor with about 75 post office boxes was blocked off because of damage.

Police said that neither Chester nor the Toyota Sienna's driver, a 48-year-old Mount Vernon woman, were injured in the accident, which was reported around 9:35 a.m. Tuesday, police said. Postal workers drove Chester from the Post Office on Cleveland Avenue to Skagit Valley Hospital to have doctors check him as a precautionary measure, Monty said.

The exact cause of the crash isn’t clear. Police said the driver may have mixed up the brake and accelerator pedals.