Imperial in Sarnia has been fined over $400,000 for the release of waste water into the St. Clair River nearly three years ago. The company was convicted late last year under the Ontario Water Resources Act, and has been given six months to pay a $325,000 fine plus a victim surcharge of $81,250. On April 18, 2016, Imperial began a planned cleaning of the cogeneration unit's heat recovery steam generator boiler, using a chemical cleaning procedure for the first time. Court heard that the following day, during a second attempt at the procedure, drainage valves were left open allowing acid solution to discharge into the clean water sewer, and eventually into the river. Over about an hour, 21 to 43 barrels of low pH solution mixed with three million litres of water, was released. In addition to the fine, on June 6, 2016, Imperial also paid an Environmental Penalty Order for $36,950 in connection with the incident.