The natural gas explosions and fires in Massachusetts last September have cost Columbia Gas more than $1 billion.

NiSource, Columbia’s parent company, said in a financial report filed this week that $757 million of that was for third-party claims against the utility, including property damage. Another $266 million was for other expenses, including the workers needed during the recovery effort.

The financial losses do not include the cost of pipeline replacement, or the costs of settling lawsuits, or fines and penalties.

The explosions in Lawrence, Andover and North Andover killed one person, injured about two dozen, damaged more than 100 structures and left thousands without heat or hot water for weeks.

The disaster remains under investigation by the National Transportation Safety Board, but was blamed on over-pressurized gas lines.

FILE-- In this Sept. 14, 2018 file photo, a worker with Columbia gas stands over an open manhole as the crew works to make sure there are no gas leaks at the corner of Parker and Salem Streets in Lawrence, Mass. (AP Photo/(AP Photo/Mary Schwalm, File)
FILE– In this Sept. 14, 2018 file photo, a worker with Columbia gas stands over an open manhole as the crew works to make sure there are no gas leaks at the corner of Parker and Salem Streets in Lawrence, Mass. (AP Photo/(AP Photo/Mary Schwalm, File)