875—140.1 (89B) Signs required and adoption by reference. The employer shall post signs which will comply with this rule. An employer need not comply with the sign posting requirements of subrule 140.1(2) if the building, structure, or location within the building or structure does not contain a significant amount of the hazardous chemical as defined in subrule 140.4(1). The National Fire Protection Association’s standard system for identifying fire hazards of chemicals based on NFPA standard 704-1980 is adopted by reference.
	   140.1(1) Size. The signs shall be at least 7½ inches on each side. The sign shall have four spaces each at least 3¾ inches on a side. Numbers and symbols within each of the four spaces shall be at least 3 inches in height.
	   140.1(2) Location. If a building or structure has a floor space of 5000 square feet or less, an employer shall post signs on the outside of the building or structure identifying the type of each hazardous chemical contained in the building or structure. If the building has more than 5000 square feet, the employer shall post a sign at the place within the building where each hazardous chemical is permanently stored to identify the type of hazardous chemical. If the hazardous chemical is moved within the building, the employer shall also move the sign or post an additional sign at the location where the hazardous chemical is moved. This subrule applies to significant amounts of a hazardous chemical as defined in subrule 140.4(1).
	   140.1(3) Categories. The signs shall identify hazards of a chemical in terms of three principal categories, namely, “health,” “flammability,” and “reactivity (instability)”; and indicate the order of severity numerically by five classifications ranging from four, indicating a severe hazard, to zero, indicating no special hazard. This information is to be presented by a spatial system of diagrams with “health” always being on the left; “flammability” at the top; and “reactivity (instability)” on the right. Color backgrounds and numbers are used for the three categories with blue representing “health” hazard, red representing “flammability,” and yellow representing “reactivity (instability).” The fourth space shall be at the bottom and used to indicate unusual reactivity or other special hazard warnings in black and white colors.
	   140.1(4) Explosives exemption. Any building or structure, other than an explosives manufacturing building, approved for the storage of explosive materials shall have signs located so as to minimize the possibility that a bullet shot at the sign will hit the magazine.