BOSTON -- The public has through Wednesday to weigh in on a natural gas rate hike set to go into effect March 1. An Aug. 1 settlement agreement would let Columbia Gas of Massachusetts increase its distribution rates by $33.2 million. The case is still open before the Massachusetts Department of Public Utilities, and the deadline for public comment is Sept. 19. Instructions for submitting comment can be found on the state's website. The case is under DPU docket number 18-45, and relevant documents are available online. Columbia Gas, a subsidiary of NiSource, has more than 313,000 customers in 65 Massachusetts cities and towns. The public input deadline comes days after explosions and fires linked to Columbia Gas killed a young man, injured others, destroyed homes, and forced a mass evacuation in the Merrimack Valley, north of Boston. The incident remains under investigation by the National Transportation Safety Board.