State officials are accusing FedEx of more than 1,500 hazardous waste violations since 2008.
In a complaint filed in Sacramento County court on Thursday, California's Department of Toxic Substances Control said FedEx Ground Package System, Inc. transported hazardous waste packages through hubs without authorization and failed to properly handle broken and leaking packages containing hazardous materials such as acids and batteries.
The agency also alleges that FedEx unlawfully received and stored hazardous waste at its three California hubs in Sacramento, Los Angeles and San Bernardino counties.
Paul Kewin, of the Department of Toxic Substances, said the violations undermine the state's ability to protect Californians.
Each violation carries a penalty of up to $25,000.
FedEx spokeswoman Katie Wassmer denied the claims, saying FedEx follows local, state and federal reporting requirements.