There was a hydrocarbon vapour release at Shell's Corunna site Wednesday morning.
In a Facebook post, Aamjiwnaang First Nation Emergency Planning reported that the leak happened at around 6:20 a.m.
The post said there's no off-site impact and air monitoring was being conducted.
Local media were not directly notified of the incident by Shell, and there was no report to the public on the Community Awareness and Emergency Response line Wednesday morning.