Day by day: How the crisis unfolded

Sept. 13: Multiple gas explosions and fires in the Merrimack Valley are reported, causing a large-scale evacuation in Andover, North Andover and South Lawrence. Gas and electricity are shut off, leaving communities in the dark as residents find refuge and schools are used as shelters. Sept. 14: NTSB officials arrive in Lawrence to launch an investigation; Gov. Charlie Baker declares state of emergency to allow Eversource to take over restoration efforts after slamming Columbia Gas’s response. Sept. 15: NTSB official announces issues with pressure sensors on an out-of-service pipeline could be cause of overpressure situation; Gov. Baker lays out timeline for gas restoration during press conference with city and town officials. Sept. 18: Columbia Gas opens claims center; Andover reports 300 claims are made that day. Sept. 19:Andover reports shower trailers are now open for residents who do not have hot water. Sept. 21:A class action lawsuit is filed in Essex Superior Court, which Lawrence Mayor Daniel Rivera slams. Sept. 22: Columbia Gas hosts job fair in Andover for multiple positions, including customer service representatives, IT professionals, plumbers and electricians; town/city officials and National Guard members begin distribution of hot plates and space heaters to residents impacted. Sept. 24: Construction crews begin working to restore gas service to affected areas, according to Andover. Sept. 26: Plumbers, electricians and building inspectors begin entering homes and businesses of areas impacted by the explosion to assess which are ready for gas restoration and which appliances need to be replaced. Oct. 2: Columbia Gas announces restoration plan for Greater Lawrence, which includes deploying 200 construction crews to meet a Nov. 19 deadline. Oct. 5: Columbia Gas and officials announce alternative housing options for impacted customers, which includes hotel rooms, apartments, travel trailers, warming centers and shelters. Oct. 6: Columbia Gas says 16 miles of a projected 50 miles of pipe has been replaced. Oct. 11: NTSB releases preliminary report on Merrimack Valley gas explosions. Oct. 12: Department of Public Utilities places a moratorium on Columbia Gas performing work beyond restoration until Dec. 1. Oct. 17: Columbia Gas launches a “Back-to-Business” initiative to expedite approving claims and restoring gas to businesses impacted. Oct. 25: Family of Leonel Rondon files wrongful death suit against Columbia Gas. Oct. 26: Gas company consultant announces that it will miss its deadline; new deadline set for sometime between Dec. 2 and Dec. 16. Nov. 1: Criminal investigation opened on Columbia Gas parent company NiSource related to gas explosions; second wrongful death suit against Columbia Gas filed. Nov. 10: Columbia Gas officials host a community open house in Andover, North Andover and Lawrence; announce gas service has been restored to 42 percent of all residential meters and 60 percent of all business meters.