Effective January 2, 2015, new Massachusetts Department of Environmental Protection (MassDEP) Underground Storage Tank (UST) Regulations (310 CMR 80.00) address the registration, installation, operation, maintenance, closure and inspection of UST systems used to store petroleum fuels and hazardous substances. The new MassDEP rules replace DFS regulations at 527 CMR 9.00, which were rescinded on January 1, 2015. Although the fundamentals of the program remain the same, the new regulations do contain some important new requirements.