AmeriGas Partners L.P. of King of Prussia today said it agreed to buy Shell Gas USA, which owns and operates a retail propane distribution business.

Terms were not disclosed, but Shell sells more than 13 million gallons of propane annually to nearly 20,000 customers from twelve locations in Michigan. The sale is expected to be completed during the second quarter.

AmeriGas Partners is the nation's largest retail propane marketer, serving nearly 1.3 million customers from 600 locations in 46 states. Its shares were up 76 cents $38.01 in morning New York Stock Exchange trading.