ANSI Z535 Standards: Complete Guide to Safety Signs & Labels

Key Takeaways

• ANSI Z535 standards define how safety signs, labels, tags, and messages should look and function.

• These standards improve hazard recognition, reduce workplace injuries, and support regulatory compliance.

• ANSI standards are voluntary, but OSHA frequently references them as accepted best practice for workplace safety.

• The Z535 series covers physical signage, product safety labels, manuals, and digital safety information.

• Using compliant safety signs and labels shows a good-faith effort toward worker protection and risk management.

What Are the ANSI Z535 Standards?

ANSI Z535 is a series of American National Standards developed to standardize the design, color, wording, and use of safety signs and labels in workplaces and facilities across the United States. Before ANSI Z535 standards, safety signs varied widely in color, wording, and layout. This caused confusion, especially for workers moving between sites or operating unfamiliar equipment.

That standardization is especially important in industrial settings where people are making fast decisions in noisy, distracting conditions. In one of our studies, it was revealed that 1 in 4 workers (25%) said a coworker had been injured, and 1 in 20 (5%) said they themselves had been hurt because a hazard sign was unclear or went unnoticed. In a real case, a CDC/NIOSH FACE fatality report details the death of a 64-year-old janitor who climbed inside the compacting chamber of a running baling machine.

In incident investigations like this, one of the first questions asked is whether hazards were clearly communicated. Sure enough, the inevstigators noted the absence of warning signs. The investigation concluded that if the machine had been affixed with safety or warning signs, they may have alerted the victim and the incident might have been avoided.

ANSI Z535 is a design standard, with its principles rooted in improving visual communication. It is developed around human factors research that supports quick recognition through:

• • Standard signal words

  • Consistent color meanings

  • Clear message layout

  • Recognizable symbols

This consistency reduces hesitation and misinterpretation, removes guesswork, and makes hazard messages easier to recognize and understand instantly.

ANSI Z535 Standards Safety Sign Requirements

ANSI Z535.1 – Safety Color Codes

ANSI Z535.1 defines standardized color meanings used throughout the entire system:

• • Red: Immediate hazard that will result in serious injury or death. Reserved for the highest-risk situations and should be used sparingly.

  • Orange: Hazard that could result in serious injury. It signals attention and caution, but where the hazard may not be as immediate or unavoidable as those requiring a Danger classification.

  • Yellow: Hazard that could result in minor or moderate injury. It is meant to alert and prompt careful behavior.

  • Blue: Important information not related to personal injury. It is used to separate operational or procedural information from hazard warnings.

  • Green: Safety equipment, emergency exits, or first aid. Directs people toward safety resources or safe actions, rather than warning them of a hazard.

Color consistency matters because workers often recognize risk level before reading text. This is why faded signs are dangerous. When colors lose contrast or shift over time due to UV exposure, chemicals, or washdowns, workers may misjudge the level of risk before they ever read the message. 

“I’ve seen too many faded, cracked, or downright missing signs to let this one slide. I always emphasize that safety signs are only effective if they are visible, legible, and relevant…Any sign that is damaged, missing, or no longer relevant should be replaced immediately.” – Rick Kaletsky, Safety consultant with over 30 years of experience in hazard recognition and abatement.

ANSI Z535.2 – Environmental and Facility Safety Signs

The second part of the ANSI Z535 covers safety signs used in buildings, job sites, and outdoor environments. It applies to fixed signs used in workplaces and public environments.

Sign Classifications

ANSI Z535.2 requires that safety signage be classified by hazard severity, using the standard signal words. The image below shows the five classification of safety signs organized along a risk-of-injury spectrum, from highest to lowest:

ANSI Z535.2 does not allow free-form sign design. Each sign must include a signal word panel, a hazard description, and safety instructions for avoiding the hazard.

Placement and Visibility

The standard also emphasizes that safety signs must be placed where the hazard is likely to be encountered, not wherever there happens to be wall space. In practice, that means:

Signs should be visible before someone reaches the hazard

Placement should follow normal lines of sight

Lighting must allow the sign to be read easily

Signs should not be blocked by doors, equipment, or stored materials

If a worker has to turn around or stop to look for a sign, it’s probably in the wrong place.

ANSI Z535.3 – Safety Symbols

ANSI Z535.3 defines the standardized safety symbols, also called pictograms, used to communicate hazards without relying on text. These pictograms are meant to shorten reaction time and help workers recognize hazards immediately. ANSI groups symbols by message intent:

In the same study we did, it showed nearly 1 in 2 industrial workers (47%) said they have misunderstood or missed a symbol on the job, which shows how often visual communication breaks down. Consistency is the key: when symbols vary by department or facility, workers pause to interpret instead of acting, and that delay creates room for mistakes.

This standard applies whether safety symbols appear by themselves or alongside text, although ANSI generally expects symbols to be paired with words unless space or conditions prevent it.

ANSI Z535.4 – Product Safety Signs & Labels

ANSI Z535.4 applies to warning labels that are permanently attached to products, not to the building or room around them. A product is any industrial equipment, tools, vehicles, or mobile equipment that pose a hazard during normal use, maintenance, or foreseeable misuse.

Label Content Requirements

The labels are built on the same core design system established in the preceding standards, which includes the following key elements:

• • Signal word panel with correct color

  • Description of the hazard

  • Consequences of ignoring the warning

  • Instructions to avoid the hazard

I’ve sat in post-incident reviews where inadequate labeling became a safety issue. One example is a U.S. auto plant case where an electrical apprentice was severely burned because the point-of-work hazard information (specifically arc-flash risk label and required PPE) was not clearly communicated on the equipment, meaning the worker lacked immediate, reliable direction at the moment of exposure during a routine task.

Durability Considerations

Labels must withstand the environment where the product is used, including exposure to heat, chemicals, moisture, abrasion, and UV light. Poor material selection is one of the most common causes of non-compliant labeling over time. ANSI Z535.4 standard expects labels to remain legible for the life of the product under normal use.

ANSI Z535.5 – Safety Tags & Barricade Tape

Temporary hazards are among the most common sources of confusion in active facilities. ANSI Z535.5 addresses this issue by providing a uniform system for temporary safety warnings, including safety tags and barricade tape.

As seen in the image above, safety tags under Z535.5 adopt the same signal word system, colors, and severity logic found throughout the ANSI Z535 standards. But, unlike safety signage or product labels, these devices are used when hazards are short-term, changing, or controlled through administrative measures.

Barricade tape serves a similar purpose by marking temporary boundaries, not by physically preventing access. The standard recognizes two standard color patterns:

• • Red/White: Indicates an immediate hazard where entry could result in serious injury or death.

  • Yellow/Black: Indicates a cautionary hazard or restricted area.

The color choice must match the hazard severity, not the convenience of what tape is available. Additionally, barricade tapes must be strung tautly and placed at a consistent, appropriate height to avoid further confusion.

ANSI Z535.5 also draws clear limits on how tags and tape may be used:

• • Tags are not physical barriers

  • Tape does not replace lockout devices, guards, or fences

  • Tags and tape must be removed once the hazard is eliminated

ANSI Z535.6 – Manuals & Instructional Materials

ANSI Z535.6-2023 sets design and formatting guidance for safety messages that appear in printed operator and owner’s manuals, assembly instructions, and other “collateral materials.” It applies when safety information is not on the product itself and not delivered through electronic or digital media.

Under this standard, safety messages in manuals are expected to follow the same structure used throughout the ANSI Z535 system. Each message should include:

• • A correct signal word (DANGER, WARNING, CAUTION, or NOTICE)

  • The safety alert symbol when personal injury is possible

  • A clear description of the hazard

  • The consequences of ignoring the message

  • How to avoid the hazard

Realistically, users rarely read manuals cover to cover. Most jump directly to the task they are trying to complete, which is why ANSI Z535.6 emphasizes placing safety messages immediately before hazardous steps.

The standard allows safety messages to be presented in several ways, depending on how the information is used:

• • A general safety section at the beginning of the manual

  • Section-level warnings that apply to a group of related tasks

  • Step-specific warnings placed immediately before hazardous actions

At the same time, the standard cautions against common mistakes that reduce effectiveness, such as:

• • Repeating the same warning multiple times without a clear reason

  • Packing too many warnings into a single page

  • Including hazards that are unrelated to the task being performed

Overall, ANSI Z535.6 emphasizes that safety messages in manuals should be clear, specific, and relevant, helping users understand risks and safe actions without overwhelming them.

ANSI Z535.7 – Safety Information in Electronic Media

The COVID‑19 pandemic accelerated the shift to digital communication, prompting manufacturers to adopt QR codes, online videos, and apps for safety information. Now, the ANSI Z535.7-2024 is established to govern how to present product safety information in electronic media using Z535-style elements where they make sense. 

It’s aimed at the real-world constraints of screens and digital experiences, including:

• • Dynamic Content: Video, animation, moving elements.

  • Interactive Content: Apps, websites, non-linear navigation.

  • Multi-modal Presentations: Visual and audio options where applicable.

  • Device Variability: Messages may appear differently across phones, tablets, computers, operating systems, and settings.

One important boundary of Z535.7-2024 focuses on presentation and format, and it does not tell you what safety content must be delivered digitally instead of (or in addition to) print.

Key ANSI Z535 Updates Since the Long-Standing 2011 Editions

For many years, the 2011 editions of ANSI Z535 standards served as the practical baseline for safety sign and label design. Since then, updates have focused less on wholesale redesign and more on clarifying symbol use, refining label categories, and expanding the system. The table below highlights the most meaningful changes:

The Role of ANSI vs. OSHA

The American National Standards Institute (ANSI) develops voluntary consensus standards that describe how to effectively communicate hazards. The Occupational Safety and Health Administration (OSHA), by contrast, is the federal agency that determines when this hazard communication is required at work and enforces those requirements through inspections and citations.

Because OSHA’s goal is an effective hazard communication system, its federal regulations often reference ANSI standards as a reference point for safety sign design. For example:

• • OSHA’s main sign and tag regulation for general industry, 29 CFR 1910.145 (Accident Prevention Signs and Tags), reflects the same core ideas emphasized in ANSI safety colors, signal words, and sign intent.

  • In construction, 29 CFR 1926.200(h) incorporates ANSI Z535.5 (Safety Tags) by reference, formally recognizing the latter’s design and use requirements for safety tags in construction settings.

In practice, OSHA inspectors often expect signage and labels to follow ANSI formats, even when the regulation itself does not name a specific Z535 section.

ANSI Z535 Standards FAQs

Is ANSI Mandatory?

ANSI standards are voluntary, not laws. However, they often become effectively mandatory in practice because:

• • OSHA frequently references ANSI Z535 in enforcement actions and citations.

  • Courts use ANSI standards to judge whether warnings were reasonable.

  • Many contracts, insurance policies, and procurement rules require ANSI-compliant safety signs and labels.

If a workplace incident occurs, failure to follow ANSI Z535 can be used as evidence that hazards were not properly communicated.

What role do NEMA enclosure ratings play in ANSI Z535 safety labeling?

The National Electrical Manufacturers Association (NEMA) enclosure ratings help define the environmental and electrical conditions that ANSI Z535 safety labels must address. The rating indicates the type of protection an enclosure provides against hazards such as electrical shock, water, dust, or corrosion, which guides the selection of the correct signal word, message content, and durability of the label.

Thus, if an enclosure’s NEMA rating changes or is exceeded by site conditions, the associated ANSI Z535 warnings may need to be updated to reflect new or increased risks.

Where do ANSI Z535 standards apply?

OSHA/ANSI Safety Sign Standards applies wherever hazards need to be communicated visually or through written safety messages, including industrial machinery and equipment, construction sites and facilities, warehouses and logistics centers, public buildings and commercial spaces, product labels and packaging, operator manuals, instructions, and training materials, and digital displays and electronic instructions.

Where should safety signs be placed according to ANSI Z535?

ANSI Z535 requires safety signs to be placed where they are clearly visible before exposure to the hazard. Key placement rules include:

• • At the point of hazard, not after it.

  • At the normal line of sight and readable distance.

  • Before a task begins, not buried in background areas.

  • Repeated only when necessary to address different exposure points.

How do I ensure my signs and labels comply with ANSI Z535?

You can check OSHA/ANSI Safety Sign Standards compliance by confirming that each safety sign or product safety uses the correct signal word and color, clearly explains the hazard and its consequences, and tells you how to avoid it. Make sure the sign is easy to see before you reach the hazard and that similar hazards are marked consistently throughout the workplace.