LAWRENCE, Mass. (AP) — A strong gas odor has brought officials back to one of the Massachusetts communities rocked just days ago by natural gas explosions and fires.

Firefighters and gas workers returned Saturday morning to a commercial area on the south side of Lawrence where they were seen opening manholes, testing gas levels and trying to gain access to businesses.

WCVB-TV reports the situation appeared to be contained by 11:15 a.m.

Officials, meanwhile, are also warning about donations scammers.

They say residents in Lawrence and Andover have received calls from individuals falsely claiming they're collecting donations on behalf of a local firefighter's association for the disaster.

A series of gas explosions Thursday killed a teenager, injured dozens, damaged homes and forced thousands of people to evacuate.

Federal and state officials are investigating.