Trade associations representing the energy industry have joined pipeline safety groups in support of a natural gas transmission pipeline safety rule that has been under consideration by the Pipeline and Hazardous Materials Safety Administration (PHMSA) since 2011.

In a letter sent earlier this month, the industry groups urged Department of Transportation (DOT) Secretary Elaine Chao "to act expeditiously to advance this important update" to the regulations.

Executives signing the letter represent the American Gas Association, the American Petroleum Institute, the American Public Gas Association and the Interstate Natural Gas Association of America. Other signatories included leaders from the Pipeline Safety Coalition and Pipeline Safety Trust.

"PHMSA's rule will advance gas transmission pipeline safety by defining specific requirements to facilitate the use of 21st century pipeline safety technologies and processes," the groups wrote. "The rule provides a foundation upon which PHMSA can better promote the utilization of modern pipeline inspection technologies, recognizing the safety, environmental and consumer benefits that such technologies can provide."

The proposed rule would allow pipeline operators to use noninvasive tools to analyze pipe conditions and identify sections needing repair or replacement, the letter noted. It also would establish requirements for operators to test certain existing pipelines to ensure they meet current safety standards.

The proposed rule is one of 42 mandates contained in the Pipeline Safety, Regulatory Certainty and Job Creation Act of 2011.

"While our organizations sometimes disagree about the specifics of pipeline safety regulations, in this case consensus was achieved on many important pipeline safety topics through the advisory committee process," the groups said. "The advisory committee ultimately provided PHMSA with recommendations to support finalizing the rule."

PHMSA, a Transportation agency, is tasked with enacting and enforcing regulations governing energy resources transport, including oil and natural gas pipelines, as well as other hazardous materials. It oversees 2.6 million miles of pipeline across the United States.

Congress has been critical of PHMSA for years. In 2015, House lawmakers blasted the agency for failing to implement all 42 mandates contained in the 2011 law.

PHMSA has also attracted the ire of the DOT's Office of Inspector General (IG), which said in 2014 that the agency had done a lackluster job to ensure state regulators enforced operators' compliance with federal pipeline safety regulations. The IG probe was prompted by the September 2010 gas transmission pipeline rupture and explosion in San Bruno, CA, which killed eight people and injured dozens more.