Question A placard indicating hazardous materials is shaped like a: Answers Diamond. Triangle. Circle. Explanation Hazardous materials warning placards are diamond-shaped. This questions appears in the following tests: Alabama HazMat Arizona HazMat Arkansas HazMat Delaware HazMat Delaware HazMat Idaho HazMat Iowa HazMat Louisiana HazMat Maryland Tank Missouri HazMat Nevada HazMat New Mexico HazMat Ohio HazMat Rhode Island HazMat South Carolina HazMat Utah HazMat Washington HazMat Wisconsin HazMat