A Damascus man was killed and an Ellicott City woman was seriously injured in a three-car collision in upper Montgomery County, police said yesterday.

The woman's infant daughter, who was riding in a child safety seat, escaped injury, according to Montgomery County police spokesman Harry Geehreng.

He said the accident occurred during a rain shower about 4:30 p.m. Sunday when a car being driven south on Rte. 27 south of Rte. 80 by Carl Emile Dornheim IV, 20, crossed the center line and collided head-on with a northbound station wagon driven by Elizabeth Wood, 32. Wood's station wagon was then struck from behind by a northbound car driven by Harold Richardson, 36, of Mount Airy, Md.

Dornheim was pronounced dead at Montgomery General Hospital. Wood was flown by helicopter to the University of Maryland Hospital in Baltimore, where she was reported in serious condition yesterday. Wood's 6-month-old daughter, Amy, was taken to Montgomery General Hospital and released. Richardson didn't require hospitalization, Geehreng said.

Police investigators said that Dornheim had been drinking and was driving in excess of the 50 mph speed limit when his car struck Wood's.

Police said neither Dornheim nor Wood was wearing a seat belt. They did not know if Richardson was wearing one.