A person should not smoke within ____ of a vehicle placarded for Class 3 or Division 2.1 materials.

A person should not smoke within 25 feet of a placarded tank that is used to transport Class 3 (flammable liquids) or Division 2.1 (gases) materials. Additionally, no person should smoke or carry a lit cigar, cigarette, or pipe within 25 feet of any vehicle containing Class 1 (explosives), Class 4 (flammable solids), or Class 4.2 (spontaneously combustible).