Many residents of Alberton, evacuated more than two weeks ago by a train derailment, were allowed to return home during the weekend.
However, a group of about 80 residents say they will not return until they are assured that their homes and property are free of any dangerous chemicals.
Twenty cars of a Montana Rail Link train derailed early on April 11. A chlorine tanker was punctured, forcing the evacuation of nearly 1,000 area residents.
Several hundred people were hospitalized, a transient riding on the train died of inhaling the gas and traffic on Interstate 90 was detoured around the area.
Officials hoped to open the last of the evacuated areas and Interstate 90 during the weekend. However, residents are not being forced to go home.
A group called the Alberton Community Evacuees said Saturday they would not return home until MRL assures them, in a document signed by the Missoula City-County Health Department and the Environmental Protection Agency, that it is safe for all to return to their homes.