Dean A. Gallo, 58, an environmentalist and...

Dean A. Gallo, 58, an environmentalist and fiscal conservative during five terms in the House of Representatives, died yesterday at a hospital in Denville, N.J., where he was being treated for prostate cancer. Mr. Gallo, a New Jersey Republican, was diagnosed with prostate cancer in 1992 and announced in August that he would not seek a sixth term. He pushed a bill that became law that requires tankers to have two hulls after the 1989 Exxon Valdez oil spill. He was also influential in pushing through a ban on sludge dumping in the ocean.