Randy Kearney filed suit Thursday against the state's Department of Health and Human Services (DHHS).
In January, Kearney declared Larry Donnell Green dead at the scene of an accident.
Green was still breathing when he got to the morgue.
Kearney's attorneys said Kearney was acting as a volunteer firefighter that night and should not lose his license.
In June, DHHS sent the case to an administrative law judge instead.
Kearney's latest suit claims that act was unconstitutional.