Senators Frank Lautenberg (D-NJ), Joe Lieberman (I-CT), Sheldon Whitehouse (D-RI), Kirsten Gillibrand (D-NY), Ben Cardin (D-MD), and Bob Menendez (D-NJ) encouraged the Environmental Protection Agency in a November 27 letter to revise a proposed rule that would allow stationary engines that generate electricity to run without emissions controls for 100 hours per year. The group charged that the engines, operating under demand-response circumstances, would undermine a program that is intended to encourage energy efficiency and smart grid management. They did not specify what an appropriate number of hours would be. The agency published a proposed rule June 7 to allow backup, reciprocating internal combustion engines to operate for up to 100 hours during emergency and electricity peak-use periods without being subject to emissions limits.