A Lawrence man was killed and three other people were injured, including one critically, in a three-vehicle accident about an hour before sunrise this morning in Lawrence’s downtown.

Wade Collins, 44, was killed in the wreck, which occurred about 6:30 a.m. at Sixth and Kentucky streets, according to Lawrence Police.

Police said Collin’s van was traveling east on Sixth Street when he drove left of center and struck a white pickup, which was going west on Sixth in the inside lane. The impact pushed the white pickup into a green pickup, which was in the outside westbound lane, police said.

A passenger in Collins’ van, John Knackstedt Jr., 36, was critically injured and taken by air ambulance to the Kansas University Medical Center.

The driver of the white pickup truck, Kenneth Searzy, 62, Kansas City, Mo., and his passenger, John Sewell, 62, Lee’s Summit, Mo., were both taken to Lawrence Memorial Hospital and treated.

The driver of the green pickup truck, Jeff Noll, 40, Valley Falls, was not injured.

The accident tied up traffic for more than an hour this morning, slowing traffic on the southbound lanes of the Kansas River bridge.

The wreck caused extra concern for emergency crews when they found the white pickup truck was carrying radioactive material.

But it turned out to be low-strength, medical-grade radioactive material of the kind used in dentist’s offices for X-rays, and none escaped, said Lawrence-Douglas County Fire & Medical Chief Mark Bradford.