At
1910.106(e)(6)(ii)
OSHA says only that “Class I liquids shall not be dispensed into containers unless the nozzle and container are electrically interconnected.” The flammable liquids standard does not call for grounding of flammable liquid storage cabinets.
However, published materials from OSHA's Hazardous Materials course, Course 201, indicate that the requirement to ground flammable storage cabinets is found in NFPA 77. If NFPA 77 has been adopted as state or local fire code, then you would have to comply with the grounding requirement.