LAWRENCE, Mass. (AP) — A bill aimed at strengthening pipeline safety in the U.S. is being pushed by members of the Massachusetts congressional delegation in response to September's natural gas explosions and fires in the Merrimack Valley.

Sen. Ed Markey and Rep. Lori Trahan say the bill would require on-site monitoring of pressure regulation stations so employees could quickly shut off gas flow in an emergency. It would also require other safety features to help avoid over-pressurizations, blamed for the Merrimack Valley disaster.

The Democrats joined the family of Leonel Rondon, the Lawrence teen killed in the disaster to unveil the bill Monday at a fire station in Lawrence. The bill is named in honor of Rondon.

Democratic Sens. Elizabeth Warren of Massachusetts and Richard Blumenthal of Connecticut are also sponsoring the proposal.