Global News reported Friday that Imperial will not be charged for a 2017 flaring incident that lit up the night sky at its Sarnia plant.
Photos and video taken from across the St. Clair River in Michigan February 23, gave the impression of an inferno at the plant.
There was also a small grass fire along a fence line between Imperial and ARLANXEO.
Global said the environment ministry would not provide a detailed explanation as to why charges were not laid.
BlackburnNews.com reported previously that the plant lost air supply to several processing units, resulting in three of four on-site flares lighting up.
Refineries commonly use flaring to burn off excess flammable gases.
Imperial reported the incident to the ministry's Spills Action Centre, notified the surrounding community, and monitored the flaring.
At the time, the ministry said air monitoring was conducted and no abnormal contaminant levels were identified.
An Environmental Bill of Rights investigation was launched in response to an application filed by Aamjiwnaang First Nation's Vanessa Gray and Ecojustice Scientist Elaine MacDonald.
