Police had closed a 100-kilometre stretch of Highway 40 Friday afternoon south of the communities of Grande Prairie and north of Grande Cache because of a sour gas leak at a well site about 110 kilometres south of Grande Prairie.
Mounties say they closed it as a precaution to protect motorists passing through the area, which is sparsely populated.
However, Mounties say they were advised by the Energy Resources Conservation Board that emergency crews had responded and there was no threat to public safety.
Police also say they were asked to reopen the highway immediately.
Sour gas is a poisonous natural gas that contains hydrogen sulphide and is colourless, flammable and smells like rotten eggs.
Police say there are no indications that the incident at the well site was a result of a criminal act.