Who must label hazardous materials? Question Who must label hazardous materials? Answers The shipper The loader The driver Explanation The shipper of hazardous materials is responsible for packaging, marking, and labeling the materials. They must supply the warning placards. This questions appears in the following tests: Alaska HazMat Arizona HazMat Hawaii HazMat Idaho Tank Louisiana HazMat Maine HazMat Maryland HazMat Michigan HazMat Missouri HazMat New Mexico HazMat Ohio HazMat Oklahoma HazMat Rhode Island HazMat Virginia HazMat Washington HazMat Washington HazMat