Regional air-quality regulators have fined United Airlines nearly $400,000 for allegedly ignoring pollution requirements and failing to ensure properly functioning filtering equipment at its maintenance facility. According to the assistant counsel for the Bay Area Air Quality Management District, the $382,500 fine was meant to discourage “careless” behavior by United and other major companies.

According to the Associated Press, more than half the fine stemmed from United’s failure to ensure the proper functioning of an exhaust system meant to clean the air during the chrome-plating of airplane parts. United technicians operated the exhaust system improperly for eight months and failed to fix it for several more months after inspectors pointed it out.