Columbia Gas gave bad work orders
Federal investigators probing the natural gas explosions that rocked three northern Massachusetts towns last month are blaming faulty work orders given to the work crews by the local utility.
The investigators say Columbia Gas failed to instruct the workers to deactivate pressure sensors when taking an old cast-iron gas main out of service.
When those sensors detected a drop in gas pressure in the decommissioned main on Sept. 13, the system automatically increased the pressure in the new, plastic gas main.
Within minutes, houses across Lawrence, Andover and North Andover began to explode from a buildup of natural gas.
One man was killed when the chimney of an exploding house fell on top of his car. Twenty-one people – including two firefighters – were injured.
The preliminary findings by the National Transportation Safety Board do not end the investigation into the incident.
Sen. Ed Markey, D-Mass, said the report “raises more questions than answers.”
“We need to turn over every stone and shine a light on the workings of this company and the entire industry, so that people can both trust that their gas system is safe and verify that nothing like this will ever happen again,” Markey said. “The fate of families and small businesses depends on it.”
Distribution pipelines operated by local natural gas utilities often operate at different pressures throughout the systems. The Columbia Gas system in Lawrence used 14 different gas regulators to ramp the pressure up or down as gas moves to customers.
Low pressure can be dangerous. When sensors detect a loss of pressure, systems compensate by adding more gas.
The result in Lawrence was pressures 12 times higher than the system was designed for.
A Columbia Gas control room in Ohio noticed the pressure spike at 4:04 p.m. The first 911 call for a house fire came at 4:11 p.m.
The NTSB investigators say the work crews followed the instructions they were given.
“Columbia Gas developed and approved the work package executed on the day of the accident,” the NTSB investigators say in their preliminary report. “The work package did not account for the location of the sensing lines or require their relocation to ensure the regulators were sensing actual system pressure. The work was performed in accordance with steps laid out in the work package.”
The NTSB said it will continue to investigate Columbia Gas procedures and its coordination with emergency responders once it noticed the pressure spike.
Nisource, the parent company of Columbia Gas, said it was cooperating with the investigation, but would not discuss it until the final report is issued.
“However, we can say that, because safety is our top priority, in the hours immediately after the incident we suspended similar work and enhanced procedures related to our low pressure systems,” Nisource President Joe Hamrock said in a statement. “We saw these as responsible steps to take in the aftermath of the incident and while the facts were being gathered.”
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