SAN FRANCISCO (AP) -- URS Corp., an engineering and construction company, said Monday that former U.S. Senator William H. Frist has joined its board, effective immediately.

Frist is a partner at Cressey & Company LP, a private investment firm, and serves as a professor of business and medicine at Vanderbilt University.

He served as U.S. senator for Tennessee from 1995 until 2007 and was majority leader of the U.S. Senate from 2002 until 2007.

URS shares declined 4 cents to $44.78 in morning trading.