Richard Harry Hefter Jr., 54, a Prince William County planning commissioner and longtime Environmental Protection Agency official, died Oct. 21 in an automobile collision near his home in Gainesville.

His car was struck by a vehicle driven by a 63-year-old man from Manassas. No charges have been filed, and the crash is under investigation by Prince William County police.

Mr. Hefter served on the county planning commission from 1986 to 1989 and from 1992 to 1995. He was appointed in March to another three-year term.

In 1994, Mr. Hefter was the only member of the commission to vote against a large-scale theme park, Disney's America, that would have been built by the Walt Disney Co. in his district near Manassas National Battlefield Park, a historically significant battlefield of the Civil War. When other commissioners praised the proposed park as a financial windfall for the county, Mr. Hefter warned that it was an "awesome planning blunder."

Before casting his vote against the Disney development, he told The Washington Post: "I know a lot of people on both sides. You have to walk a very fine line. But if [this Disney vote] winds up costing me a friendship, to hell with that friendship."

Opposition from preservation groups and from the broader community was so strong and vocal that Disney eventually withdrew.

Mr. Hefter was also known for his spirited opposition to what he saw as conflicts of interest among members of the county Board of Supervisors active in the building industry.

For 26 years, Mr. Hefter worked for the EPA in Washington in a variety of analytical roles. He specialized in evaluating toxicology reports of hazardous chemicals. In his most recent position, he was chief of the High Production Volume Chemicals Branch and was considered a senior EPA official. He received many awards for his work before retiring in July.

He was born in Philadelphia and graduated from Delaware Valley College in Doylestown, Pa. He received a master's degree in technology and public policy from Washington University in St. Louis in 1977.

He was a founding member of the Northwest Prince William Civic Association and was a member of the American Chemical Society. He was active in Gainesville District Little League and the Gainesville Ruritans, a community group.

Survivors include his wife of 26 years, Philomena Stanley Hefter of Gainesville; two children, Richard Thomas Hefter and Sarah Hefter, both of Blacksburg, Va.; and his mother, Naomi "Jerry" Hefter of Philadelphia.

Richard Harry Hefter Jr. was recently appointed to a third term as a Prince William planning commissioner.