In This Issue

NTSB Emergency Recommendation in response to the Merrimack Valley Incident

[Docket No. PHMSA-2018-0073]

On September 13, 2018, a series of explosions and fires occurred after high-pressure natural gas was released into a low-pressure gas distribution system in the northeast region of the Merrimack Valley, Massachusetts. The distribution system was owned and operated by Columbia Gas of Massachusetts, a subsidiary of NiSource. The National Transportation Safety Board (NTSB) has issued five urgent safety recommendations as investigation of this incident continues:

To the Commonwealth of Massachusetts:

Eliminate the professional engineer licensure exemption for public utility work and require a professional engineer’s seal on public utility engineering drawings. (P-18-005)

To NiSource:

  1. Revise the engineering plan and constructability review process across all of your subsidiaries to ensure that all applicable departments review construction documents for accuracy, completeness, and correctness, and that the documents or plans be sealed by a professional engineer prior to commencing work. (P-18-006) (Urgent)
  2. Review and ensure that all records and documentation of your natural gas systems are traceable, reliable, and complete. (P-18-007) (Urgent)
  3. Apply management of change process to all changes to adequately identify system threats that could result in a common mode failure. (P-18-008) (Urgent)
  4. Develop and implement control procedures during modifications to gas mains to mitigate the risks identified during management of change operations. Gas main pressures should be continually monitored during these modifications and assets should be placed at critical locations to immediately shut down the system if abnormal operations are detected. (P-18-009) (Urgent)

The preliminary report and related recommendations can be found on the NTSB Investigations webpage.