Seventeen people were kept overnight at Portneuf Medical Center in Pocatello after a reported hazardous materials incident Friday afternoon at a local truck stop, the hospital reported.

But the Pocatello Fire Department said late Friday night that after several hours of investigating what was reported as an unusual odor at Bannock Peak Truck Stop and Casino on the Fort Hall Indian Reservation, no evidence of a hazardous substance was found.

PMC officials said that all 17 of the people transported via ambulances to the hospital from Bannock Peak were released on Saturday morning. The 17 people were kept under observation at PMC as a precaution.

The mysterious smell was first reported around 3:40 p.m. Friday at Bannock Peak Truck Stop and Casino, located off Interstate 86 between Pocatello and American Falls. The Fort Hall Fire Department initially responded and at 4:20 p.m. tribal authorities decided to close and evacuate Bannock Peak and call in the Pocatello Fire Department’s hazardous materials team to investigate the odor.

Numerous people who were at Bannock Peak at the time were then transported to PMC. Seventeen of those people were kept at PMC overnight for observation.

The Pocatello Fire Department’s hazardous materials team remained at Bannock Peak for several hours but could not detect any dangerous fumes or find any other hazardous substances in the building, the Pocatello Fire Department said late Friday night.

PMC reported that it declared a “Code Black” alert at 5:13 p.m. Friday because of the Bannock Peak incident. The alert essentially ordered all PMC employees currently at the hospital to remain there until further notice because of a mass casualty incident.

Decontamination tents were set up outside of PMC on Friday so that everyone transported there from Bannock Peak could go through a precautionary decontamination process before entering the hospital, PMC officials said.

The Pocatello Fire Department’s hazardous materials team arrived at Bannock Peak around 5:15 p.m. Friday to investigate the mysterious smell.

The Pocatello Fire Department said the people at the truck stop were transported via ambulances to PMC after some of them reported that they weren’t feeling well.

The Shoshone-Bannock Tribes took the Bannock Peak incident seriously enough that they activated their emergency operations center to coordinate the emergency response.

Tribal authorities issued a press release early Saturday morning about the incident, saying the unusual odor was contained to the Bannock Peak building, there was never a threat to the surrounding community and Bannock Peak has been declared safe and can reopen.

The Bannock Peak truck stop reopened later Saturday morning but the casino portion of the building remains closed and won’t reopen until Sunday or Monday, officials said.

Tribal authorities said they will continue to investigate to determine the source of the smell.