Valero Energy Corp. claims in a federal lawsuit filed Monday that New Jersey lawyer Seth Davenport overbilled the company by at least $1.1 million in connection with a long-running tax appeal.

Davenport has demanded fees bearing no relation to what is called for in a 2013 fee agreement with Valero, claims the lawsuit filed in New Jersey. Davenport is a solo practitioner in Montville who has represented Valero since 1998 in its appeal of the assessment on its Paulsboro refinery in Gloucester County.