OSHA 1915.91
Accident prevention signs and tags
Subpart F
Questions & Answers
Under 1915.91, when should an employer use an accident prevention sign or tag instead of other controls?
Use a sign or tag when engineering controls, administrative controls, or barrier methods cannot fully eliminate or control the hazard. The 1910.145 requirements apply when a conspicuous sign or tag is needed to warn employees about hazardous conditions or to identify equipment status that cannot be made safe by other means.
Under 1915.91, what is the difference between a 'sign' and a 'tag'?
A sign is a fixed panel or display intended to convey a safety message at a location, while a tag is a durable, legible notice attached to equipment or an item to indicate hazard or status. 1910.145 distinguishes these forms so employers use the appropriate device for permanent warnings (signs) or temporary/status indications (tags).
Under 1915.91, what basic information should a tag include when it's used to indicate equipment must not be operated?
A tag should clearly state the hazardous condition or status and identify the person responsible, so others know why the item is restricted. The tag should include a message such as "Do Not Operate," the identity of the person who placed the tag, the date, and the reason for placing it; these content and legibility expectations derive from 1910.145.
Under 1915.91, where must accident prevention signs and tags be placed to be compliant?
Signs and tags must be placed so they are conspicuous and can be readily seen and read by people who need the information. 1910.145 requires that the devices be located to warn of the hazard or to identify status at the point of potential exposure or control.
Under 1915.91, are pictograms and multiple languages allowed on signs and tags?
Yes — pictograms and text in additional languages are allowed to improve clarity. 1910.145 permits use of symbols and clearly worded legends and employers should use symbols or translations when they help employees understand the hazard.
Under 1915.91, do employers have to follow OSHA's safety color code on signs and tags?
Yes — employers should follow the safety color code and sign classifications described in 1910.145 (for example danger, warning, caution, safety instruction) so that the sign's color and legend match the hazard severity and the recognized convention set out in the standard.
Under 1915.91, what is the practical difference between 'Danger', 'Warning', and 'Caution' signs?
Use 'Danger' for hazards that will cause death or serious injury immediately, 'Warning' for hazards that could cause death or serious injury, and 'Caution' for non‑fatal or minor injuries. These conventional distinctions and their intended uses are defined in 1910.145.
Under 1915.91, can a tag be used by itself as the only method to prevent energization during maintenance?
No — a tag alone should not be the sole method of hazard control when it cannot provide positive protection against energization; employers must follow energy control procedures in the Lockout/Tagout standard. See 1910.145 for tag use and consult the Lockout/Tagout requirements under 1910 and OSHA's interpretation clarifying that temporary re-energization or other alternatives require documented protective measures in accordance with the control of hazardous energy guidance (see OSHA letter of interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2024-10-21).
Under 1915.91, when is it acceptable to temporarily remove lockout/tagout devices to test or reposition equipment?
Temporary removal of lockout/tagout devices to test or position machinery is allowed only when necessary and only after following a prescribed sequence that protects employees. This limited exception and required sequence are described in the Lockout/Tagout provisions referenced in 1910 and explained in OSHA's interpretation about minor servicing and temporary re-energization at https://www.osha.gov/laws-regs/standardinterpretations/2024-10-21.
Under 1915.91, do signs and tags need to be maintained, and what maintenance is required?
Yes — signs and tags must be kept legible, clean, and replaced when worn, defaced, or no longer understandable. 1910.145 requires that accident prevention signs and tags remain in a condition that allows employees to read and understand the message.
Under 1915.91, are temporary signs allowed and how should they differ from permanent signs?
Yes — temporary signs are allowed when needed for short-term hazards, but they must meet the same clarity, legibility, and safety-color principles as permanent signs. 1910.145 governs both temporary and permanent devices; the employer must ensure the temporary sign effectively warns and is visible for the duration of the hazard.
Under 1915.91, can employers use their own sign designs if they deviate from OSHA examples?
Employers can use custom signs provided they convey the required hazard information clearly and are consistent with the safety color and classification principles in 1910.145. Employers should not use designs that reduce clarity or conflict with the intent of the standard.
Under 1915.91, how should an employer decide the lettering size and visibility for a sign or tag?
Choose lettering size and sign dimensions so the message is legible at the expected viewing distance and under expected lighting; 1910.145 requires that size and design be appropriate for effective communication of the hazard to those who need the information.
Under 1915.91, are illuminated or reflective signs required when visibility is poor?
Yes — when normal lighting or conditions would prevent employees from seeing a sign, employers must provide illumination or reflective materials so the sign remains visible and effective. This requirement follows the intent of 1910.145 to ensure warnings are conspicuous under expected conditions.
Under 1915.91, do shipyard employers have to train workers about the meaning of signs and tags?
Yes — employers must make sure employees recognize and understand the meaning of the signs and tags used in the workplace so warnings are effective. While 1910.145 sets the sign/tag requirements, employer training obligations across OSHA standards (for example lockout/tagout procedures and hazard communication) make employee understanding an essential part of compliance.
Under 1915.91, are floor marking systems allowed instead of signs for marking hazardous areas?
Floor marking systems may supplement signs but should not replace required signage where a sign is specifically needed to convey hazard information. Use of floor markings must still achieve the same clear communication expected by 1910.145; do not rely on floor markings alone when a sign or tag is required to warn of a hazard or identify equipment status.
Under 1915.91, must valves, switches, and control devices be tagged when they are out of service?
Yes — when control devices are taken out of service and could present a hazard if operated, they should be tagged to indicate their status and prevent inadvertent use. 1910.145 covers the use of tags to identify equipment condition and provide clear instructions to employees.
Under 1915.91, if an employer follows ANSI or other consensus sign standards, is that sufficient to meet OSHA requirements?
Following recognized consensus standards can be useful and often aligns with OSHA expectations, but employers must still meet the requirements of 1910.145. OSHA values consensus standards for guidance, but has not automatically adopted all alternative methods; see OSHA's discussion about alternative methods and lockout/tagout interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2024-10-21 for related context where OSHA explains it has not accepted alternative methods in all cases.