As federal investigators continue their probe into the Sept. 13 Merrimack Valley gas disaster, the National Transportation Safety Board on Thursday issued a series of safety recommendations it classified as "urgent."
The NTSB released a report with four recommendations for NiSource, the parent company of Columbia Gas, and one for the state, seeking elimination of the professional engineer licensure exemption for public utility work and a requirement for a professional engineer's seal on public utility engineering drawings.
The report recommends NiSource do the following:
- revise the engineering plan and constructability review process across all subsidiaries
- review all records and documentation of natural gas systems,
- apply management of change processes to all changes to identify threats that could result in a common mode failure
- develop and implement control procedures during gas main modifications to mitigate risks
In a statement, Sens. Edward Markey and Elizabeth Warren called on NiSource to implement the recommendations immediately.
"Columbia Gas failed to keep track of what projects were being done on their gas system," the senators said. "It failed to prioritize safety when conducting those projects. And it failed its customers, the residents of the Merrimack Valley, and the public trust."
As of Thursday morning, Columbia Gas had restored service to 3,835 of the approximately 7,500 residential meters that were without gas since the fires and explosions that killed one person and damaged homes across Lawrence, Andover and North Andover.
"Since the September 13th event, NiSource has identified, and moved ahead with, new steps to enhance system safety and reliability and to safeguard against over pressurization. Some of these measures have already been completed and others are in process," NiSource said in a statement.
Those measures, according to the company, "will include fail-safe measures called for in NTSB's recommendations today."