HAMILTON, Mont. -

Highway 93 north of Hamilton is now reopened after being closed for several hours Friday. 

A Norco truck carrying three chemicals including liquid nitrogen and liquid oxygen had an accident just before noon.  The trailer detached from the truck and crashed onto the highway. 

Troopers on the scene tell NBC Montana some of the liquid oxygen leaked from the tank.  

Authorities shut down Highway 93 between Woodside Cutoff and Sheafman Creek. 

Ravalli County Sheriff Chris Hoffman ordered evacuations of homes for about a half-mile around the crash site. Late Friday afternoon, crews were attempting to safely move the trailer and chemicals off Highway 93. 

Authorities are investigating this as a mechanical failure in the trailer attachment.  Highway Patrol says this was a Norco company truck making a normal delivery to a store in Hamilton.