A Maverik convenience store in Lander will replace an electronic leak monitoring system on its underground gasoline storage tanks following a gasoline spill into the Popo Agie River.

The leak was caused by an underground storage tank being overfilled, according to a Wyoming Department of Environmental Quality notice of violation issued April 12.

Included with the notice was an order that the Lander Maverik stop deliveries to its regular unleaded underground storage tanks. The order will not be lifted until Maverik makes necessary repairs to the storage tanks or closes them.

On April 18, DEQ approved a work plan submitted by Maverik.

Under the plan, the Maverik will recertify existing overfill prevention devices on all underground storage tanks including replacing any defective devices. The company will also install a new system to equalize the amount of gasoline stored in the station's two regular unleaded storage tanks.

Maverik will additionally install an electronic leak detector in one of its tanks along with an audible and visual overfill alarm that can be clearly seen and heard by operators during fuel deliveries.

Because Maverik owns more than 100 gasoline tanks nationwide, it will have to provide an additional $1 million beyond the $1 million already provided by a financial assurance account.

The incident occurred in early April when Lander police and firefighters responded to a report of gasoline fumes coming from the Popo Agie River. First responders noted an oily sheen on the river's surface, which was later confirmed to be gasoline coming from an overfilled gasoline tank at the Lander Maverik.