The Pac-N-Sac convenience store located at 2100 Old Ranch Road 12 had its gas pumps closed by the Edward's Aquifer Authority Jan. 1 for exceeding the age limit for underground storage tanks. The Texas Commission on Environmental Quality requires underground gasoline tanks east of the railroad tracks in San Marcos to be double-walled but does not impose age restrictions, said Bernie Borden, who has has owned Pac-N-Sac for 28 years.