Will the ANSI designs save more lives?

| July 24, 2013

The ANSI Z535 sign designs are now sanctioned alternatives to OSHA’s traditional, straightforward templates.

But, will they save lives?

It depends! In some environments, the ANSI designs are far superior. For others, the directness and historical familiarity with the traditional OSHA Danger and OSHA Caution signs, we believe, are far better. The safety sign market, interestingly, has not shifted to the ANSI designs, even after OSHA’s acceptance of these designs.

Traditional vs ANSI Z535 Designs

OSHA’s traditional design is below on the left; an example of the potentially sanctioned ANSI Z535 sign design is below on the right.


Traditional OSHA Sign Designs follow ANSI 35.1 (from 1968)


ANSI Z535 Safety Sign Design

The ANSI Z535 designs are nuanced; they better reflect and address the complicated hazards of the modern workplace. The designs give employers another good option to consider as they safeguard their employees.

Still, the ANSI’s designs have a number of limitations and are not always the best option.  I will outline a few of the ANSI Z535 limitations for safety signs and tags in this commentary.

How ANSI Z535 designs are currently used

To date, the ANSI Z535 safety sign designs represent a tiny portion of the current warning sign market. They are used primarily with custom-designed warning signs – especially those that are used in multiple locations. The cost to design and approve these more complex warning signs discourages single-sign application. These designs are often used by electrical utilities, the transportation industry and, of course, as warning labels on equipment.

Since these designs communicate more detail, and therefore provide better legal protection in the event of an accident, you don’t have to look far to find a lawyer behind these signs’ application.  The fear of litigation and tort law drives many of the current uses of the ANSI sign designs.

Do the ANSI Z535 standards provide a superior level of protection?

With an emphasis on tested symbols and the ability to handle complex messages, the ANSI Z535 designs have many advantages.  Without doubt, the ANSI Z535 designs are better able to handle the increasingly complex hazards found in the typical workplace.


The emphasis on legibility, hazard avoidance and hazard consequences in the ANSI Z535 designs are all major advantages in an increasingly complex workplace.

No one would argue that traditional sign designs are often dangerously out of date. Changing little since the 1930s and 40s, the traditional safety sign designs don’t reflect many aspects of our 21st century environment:

  • Multi-lingual workforce. Americans are increasingly culturally diverse and English is not always a first language.
  • High job turnover. The vast majority of accidents occur in the first weeks at work, and Americans now average seven jobs in their career.
  • Illiteracy. More than 40 million Americans cannot read this paragraph. It is the illiterate workers who are most likely to work in environments with a greater risk of injury or illness.warning
  • The vulnerability of the public. More and more signs are viewed outside of the controlled environment of the factory floor. Safety signs are not just for factory workers, but for children, lab technicians, recent immigrants, service workers, or anyone who comes across buried utility lines. In fact, the fastest growing category of injury happens offsite; over $100 billion is spent annually on injuries that occurred away from workplaces.
  • More hazards with hidden or delayed impact. Electrocution, asphyxiation, and toxic gas are all hidden hazards; cancer, infertility, blood borne pathogens, and birth defects all have a delayed impact. Communicating these consequences on a sign can be difficult.
  • Increased mechanical complexity. The inside of today’s factory is much more complex than the factory of 50 years ago. Mechanical processes have given way to remote, electronic controls. The crash of a computer system can interrupt emergency responsiveness. Substation switches are radio controlled at a remote site. Simple stock signs and tags cannot convey this inevitable complexity.
  • The competition for attention. Safety signs are likely to be part of numerous other procedures: emergency response procedures, safety training systems, way-finding systems, HazCOM procedures, fire protection drills, etc. As such, warning signs are part of a complex system of postings that should not be unplanned or managed independently. They must fit into an overall communication scheme of a plant.

The downside of incorporating ANSI Z535 designs within the OSHA rules

For all their updated advantages, the Z535 designs, in many situations, are not better. There will be unintended consequences of pushing the ANSI Z535 designs for many hazards. The Z535 designs require, in most situations, more information.  By putting more information on the sign, I worry that there will be a subtle downgrading of training. Why train when the proper handling instructions are given on the sign itself?

Additionally, information can go stale. A sign that says “call x808 In Case of an Emergency” or “Wear Latex Gloves,” while better in the short term, can quickly become a hazard itself. Safety officers change. New research can emerge on proper PPE to wear. In contrast, a “Danger Keep Out” sign is evergreen.

Most safety signs can last a generation once installed. Ultimately, many environments will have a mishmash of both traditional and Z535 designs – with some accurate and others misleading. Remember that each department may install their own signs (Operations, Fire Protection, Safety, etc.) and only one or two signs are ordered at a time.

Part of the ANSI’s limitation is that it was created by committee. Driven by stakeholders in the warning industry (think label designers for equipment, symbol researchers, consultants that feed off tort litigation), the ANSI standards sometimes support the needs of the label market over the practical needs of safety signs.  Trying to harmonize safety label designs with safety sign designs has caused many problems.

Do the ANSI designs create problems for both safety signs and safety labels?

Warning signs and warning labels function differently. An implicit goal of warning labels is to defend the manufacturer in case of an accident (e.g. protecting the ladder manufacturer from liability). Warn – but don’t scare away – customers. For safety signs, the goal is reversed. We want to scare you into safe behavior.

For warning signs, there is a danger of too many exaggerated claims of hazards, essentially losing credibility by crying wolf.  For safety labels, the bias is towards complexity; for safety signs, the bias is towards a blunt and exaggerated headline. The goals for each constituency are contradictory; one seeks to diminish the perception of danger and the other wants to amplify it.

Unfortunately, the ANSI Z535 standard, while meeting many of the goals for safety labels, has some fundamental flaws when applied to safety sign designs. The failure of the ANSI Z535 safety sign standard in the marketplace, I believe, has more to do the failure of the ANSI Z535 safety sign designs themselves than with a lack of a particular OSHA reference or the nuisance of de minimus violations.



In some environments, the traditional designs will remain most common (see top left). In others, such as the PPE sign (lower right), the ANSI Z535 designs offer a greater level of clarity that safety officers appreciate.

In the Z535 designs, hazard and probability distinctions are lost on all but the most sophisticated users. The designer – and importantly the passerby potentially affected by a hazard – must make a series of very complicated probability and risk-assessment choices. Fine distinctions must be quickly made between different types of injuries and the probability of an accident.  Lawyers love it, but I’m worried about the naïve layman. You shouldn’t have to be a lawyer or a graphic designer to create a new safety sign – let alone read one. There is no time to decipher a severity and probability flow chart when face-to-face with a hazard.  Moreover, there are a number of other OSHA standards that may be in conflict[i].

Increased costs and time-to-order are also limitations for ANSI Z535 signs and tags. Certainly, digital printing, online ordering and on-demand printing have eliminated many of the additional costs for a typical (and often customized) ANSI sign or tag when compared to a traditional stock safety sign or tag. The real burden is in the design. Choosing a symbol, consistently making fine distinctions for the sign’s header, writing a complex hazard avoidance and consequence message appropriate to your environment takes time and, controversially, a sophistication that a typical small business buyer of one or two signs might not be able to supply.

Research on the ANSI Z535 designs

Little research has been done to prove that the ANSI Z535 sign designs, as a system, are significantly superior to other safety sign designs. Yes, symbols and legibility research has been done. The benefits of adding hazard avoidance information on signs are hard to dispute. Still, little critical work exists on the Z535 sign design as a whole.

Some historical research, however, throws into serious doubt the effectiveness of the ANSI Z535 design for the middle level of hazard, the orange “Warning” header. This research[ii] showed not only that this design is less legible[iii] than the other header choices, but that it is not associated with a level of hazard that the ANSI Z535 standards ascribes to this sign type (e.g. “Warning” is perceived little differently from “Caution”). In other words, the distinction between death and minor injury (e.g. Warning and Caution) is lost.

Worst still, this Warning level of hazard, if the Z535 definitions are properly interpreted, becomes the most common design for signs (with Caution as next most popular and Danger and Notice least common). As a counterpoint, DANGER (the highest level of hazard) represents over 50% of the mix for safety signs using the traditional 1968 ANSI designs[iv].




Signs using the Warning header are the most commonly used of the ANSI Z535 designs. Are we safer with a “watered down” header?

How will safety signs change if the OSHA update is accepted?

Ultimately, the impact will be minimal.  In practice, the ANSI Z535 design standards are widely ignored by most sectors of the warning sign industry.  Over 90% of the warning signs sold in United States follow the original 1968 (Z35.1) standards. The warning sign and tag market totals over $250 million annually, and the percentage following the ANSI Z535 design guidelines has changed little over the last 20, or so, years. This is frustrating for those of us who worked over the years on crafting and revising the ANSI sign and tag standards.

In many ways, I applaud the changes of the ANSI Z535 standard. After all, I helped draft many of the changes that were incorporated in the safety sign as well as the safety tag standards.  The standards are an honest and well-intended attempt to handle the trends in our industry. But, safety signs are not like U.S. traffic signs or the GHS symbols used in international chemical hazard labeling – where the need for consistent national or international standards is obvious and effective.  Warning signs and tags are emotionally and graphically complicated.

Safety signs, most of all, are advertisements for safe behavior.  Like any good advertising campaign from Madison Avenue, it is hard to construct a single design standard that is humorsignsgood for all safety signs. Someone’s life is on the line. A community’s security is at stake. The workplace is cluttered with multiple messages. Safety sign designers need a wide range of motivational tools, slogans and designs to prevent accidents – depending upon the audience, their training and the urgency of the hazard. Tools include sign repetition, accident photos or even humor.

Moreover, the notion that safety signs are a distinct category for safety messages is unsound.  How is a safety message different when shown on safety signs versus when shown on a banner, a safety scoreboard, a floor sign, barricade tape, an audio warning, user instructions on an iPad or no smoking door hanger in a hospital?

It would be arrogant to assume that a single standard is best.  The ANSI Z535 designs, the traditional safety sign and tag designs, as well as the countless other designs to come, will all have their place and will all coexist.

This is not only inevitable but good for safety.


[i] Other OSHA standards that do not match the current ANSI Z535 definitions potentially include: 1910.146, 1910.1027, 1910.1048 and 1910.1050. For example, OSHA 1910.1029 (j)(l)(i). “Signs should be posted on entrances to regulated areas that read: DANGER, BENZENE, CANCER, HAZARD, FLAMMABLE—NO SMOKING, AUTHORIZED PERSONNEL ONLY, RESPIRATOR REQUIRED.”  This is an application that, most likely, would not require the DANGER header according to ANSI Z535.

[ii] The study on Hazard Association Value of safety sign headers was published in 1995 by Human Factors Society and the authors were Kalsher, Wogalter, Brewster and Spunar. Other older research papers are by: Bresnahan,  Bryk, The Hazard association values of accident prevent signs, Professional Safety, January 1975; Chapanis, Hazards Associated with Three Signal Words and Four Colors on Warning Signs, Ergonomics, 1994; Wogalter, Silver, Arousal Strength of Signal Words, Forensic Reports, 1990; and, Silver, Gammella, Barlow and Wogalter, Connoted Strength of Signal Words by Elderly and Non-Native English Speakers, 1990 presented at the Human Factors & Ergonomics Society Meeting.

[iii] Black on orange has low contrast. Its Dmin/Dmax is not as great as black on yellow or white on red. Black and orange has a Dmin/Dmax ratio of 76%; black on  yellow is 89%.  Given an accurate assessment and definition of most hazards (according to Z535), it is probable that the orange Warning sign should become the most prevalent sign type. It is ironic, then, that the least legible sign type with the shortest history will become the most common safety sign of all.

Further work on the poor legibility of the Warning sign header, with special emphasis on aging viewers, has been performed by Dr. Donald Kline from the University of Calgary.

[iv] The sales data shown in this commentary is derived from the author’s affiliated companies and partners.


Category: News, News / New Products, OSHA