LAWRENCE (CBS) – The city of Lawrence is moving Halloween trick-or-treating up a few days early so that it won’t interfere with recovery work related to last month’s Merrimack Valley gas explosions.

Mayor Dan Rivera tweeted Tuesday that Halloween city-wide will take place on Sunday, Oct. 28 from 4 p.m. to 6 p.m. “to insure safety for all, and not get in the way of the work of the recovery” in South Lawrence.

Andover is also canceling a trick-or-treating event at the town hall that was scheduled for Halloween “due to the ongoing construction, road detours, and parking restrictions from the gas emergency.”

The Merrimack Valley explosions of Sept. 13 sparked dozens of fires across Lawrence, North Andover and Andover. The incident killed an 18-year-old and sent 21 people to the hospital.

Columbia Gas says about 3,000 workers are replacing gas mains, service lines and meters in the affected areas. Gas service is expected to be fully restored by Nov. 19.