After Clean Water Act violations related to a jet fuel storage facility at the San Francisco International Airport, $1 million in improvements will be undertaken by Chevron and SFO Fuel.

SFO Fuel, a consortium of airlines that leases a fuel tank facility at the airport, self-reported the violations to the Environmental Protection Agency in 2008. Chevron operates the facility, which has seven above-ground storage tanks with a capacity of 15 million gallons.

SFO had discovered the facility had insufficient secondary containment capacity to prevent a catastrophic spill from reaching the San Francisco Bay, according to an EPA press release. The Clean Water Act mandates that facilities be able to contain not only any spills but also “freeboard,” or potential rainfall.

SFO Fuel is installing a geosynthetic clay liner throughout the containment area.

In addition to the improvements, SFO Fuel and Chevron must pay a $177,500 penalty.