After all hazards have been
identified, analyzed, and prioritized, warning prototypes
can be designed. - by Deane Cheatham, Eric Shaver,
and Michael Wogalter
Each year, millions of people are injured in the
workplace. One of the most difficult tasks facing
employers is to identify the hazards associated with
the products and equipment used by their employees.
Such careful considerations will not only provide a
safe work environment for the employee, but protect
the employer as well, in that costs associated with
workplace injuries (loss of productivity, worker's compensation)
and litigation will be minimized.
If hazards are present in the workplace, steps
should be taken to change the work environment to remove
or minimize them. First and foremost, attempts should
be made to design the hazard out of the jobs, equipment,
tools, and environment. Of course, alternatives are
not always available or practical to eliminate all hazards.
A basic method of reducing hazards is to use
guards that prevent the employee from coming into contact
with the hazard. Guarding can be accomplished physically
(barriers) or procedurally (e.g., requiring certain
behaviors before working with equipment or tools). When
a hazard cannot be eliminated or adequately guarded
against, then, as a third step, employees should be
warned about the hazard. Employers should take steps
to ascertain that warnings are designed to maximize
the likelihood the employees will notice, understand,
and comply with them.
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Guidelines for the design
of effective warnings have been developed from
research and standards (ANSI Z535, 2002). We
describe these in the remainder of this article.
Warnings Development Paradigm
The warning development paradigm consists of
four phases: (1) planning, (2) analysis, (3)
design, and (4) evaluation.
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Who will be involved in the warnings development
process is an important consideration. Experience
in engineering, product design, marketing, and
litigation is desirable.
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Planning
Successful warning development depends on thorough planning
prior to development and testing. The objective of this
phase is to identify the focus of the warning, the amount
of time to create the warning, and available resources.
Planning also entails determining the characteristics
of the employee. These include:
Reading level
General public vs. members of a specialized field
Native vs. non-native English speakers/readers, and
Sensory modality impairment (hearing, vision, etc.).
These characteristics will help shape the warning's
design so it effectively communicates the intended message.
The average reading level of the employee needs to be
considered, to prevent using language that is not understandable.
Another consideration is whether a large percentage
of the population is non-native English users. If so,
the warning may need dual-language presentation. Finally,
potential sensory modality impairments (poor vision
or hearing) of the employees should be considered. The
use of personal protective equipment (hearing protection,
welding visors, etc.) may lessen the ability of people
to hear or see. If such devices are used, consider their
effect (e.g., use louder warnings or higher visual contrast).
Who will be involved in the warnings development process
is an important consideration. Some experience in engineering,
product design, marketing, and litigation is desirable.
Company employees may not have the knowledge or experience
to design effective warnings, so it may be necessary
to hire a consultant who specializes in warnings and
risk communication to facilitate the development process,
especially with respect to testing methods.
Analysis
The analysis phase consists of the following steps:
(1) task analysis, (2) identifying the hazards, (3)
risk evaluation, and (4) hazard prioritization. If possible,
investigate how employees will use the product and at
what points during product use the warning might be
needed. This can best be accomplished through task analysis.
Task or job analysis decomposes a task or job a person
must perform into its basic components. Once a task
analysis has been conducted, the potential hazards of
the product must be identified and evaluated to determine
the amount of risk they pose. Finally, hazards should
be prioritized so the main hazard receives greater attention
than those that would likely pose minimal danger.
Design
After all hazards have been identified, analyzed, and
prioritized, warning prototypes can be designed. The
hazards prioritized in the analysis phase will guide
which messages should be included in the warning. Each
message should include (1) an explanation of the hazard,
(2) consequences if precautionary behavior is not taken,
and (3) what can be done to protect yourself from the
hazard.
Once the aforementioned steps have been completed, the
format and design characteristics of the warning should
be defined. A start for any warning designer is adherence
to the American National Standards Institute's Z535.
This standard, revised in 2002, provides guidelines
for the development of warning signs and labels.
The sign consists of three main components: signal word
panel, symbol panel (optional), and message panel. It
should be noted that through 2002, ANSI allowed the
use of OSHA-compliant warnings, but this is no longer
the case. Because OSHA adopted a precursor to the current
ANSI Z535 standard (the precursor is ANSI Z535.1-1967),
employers who comply with the updated ANSI standard
will not result in an OSHA violation under OSHA's de
minimis policy.
Sign/Label Format
Signal words: ANSI Z535 recommends the use of
Danger, Warning, and Caution to convey decreasing levels
of hazard. Signal words conveying greater hazards will
be more effective. The signal word appears in the signal
word panel at the top of the sign/label.
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Color: The signal
word panel background/foreground text color
usage recommended by ANSI are red print on a
white panel background, black print on an orange
background, and black print on a yellow background
to convey decreasing levels of hazard for DANGER,
WARNING, and CAUTION, respectively. As an example,
assume the signal word DANGER is printed in
white on a red background to convey the greatest
hazard, according to the ANSI Z535 standard.
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ANSI Z535 recommends the use of Danger, Warning,
and Caution to convey decreasing levels of hazard.
Signal words conveying greater hazards will
be more effective.
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While the ANSI standards are guidelines to facilitate
the development of effective warnings, it is important
to note that government regulations (e.g., OSHA's 1910.145,
etc.), which require adherence by law, also must be
considered. Although adherence to ANSI Z535 standards
and technical regulations is important, other features
should be considered in designing warning signs and
labels. An effective warning should accomplish three
interrelated goals: (1) capture attention; (2) be understood;
and (3) increase compliance.
In order to capture attention, warnings must have greater
conspicuity than the context in which they appear. This
is particularly important in a work environment in which
there may be numerous activities and distractions that
compete for the employees' attention. Once the receiver's
attention is captured, he or she must comply with the
warning for it to be effective. An individual's motivation
to comply with a warning's directives is often affected
by expectations concerning the level of hazard associated
with a job or environment.
The following section presents guidelines for warning
development. Some are addressed by the ANSI standard,
and others are based on research findings. These guidelines
address both conspicuity and compliance issues.
Guidelines for Warnings Development
Format
Warning must be large enough to be seen by the intended
audience.
Left-justify the text.
Orient messages to read from left to right.
Place the most important warning statements at the
top.
Wording
Use as little text as necessary to clearly convey
the message.
Use short sentences rather than long, complicated
ones.
Be explicit--tell the reader exactly what to do
or not do.
Use short, familiar words. Avoid technical terms
and jargon.
Avoid using abbreviations unless they have been
tested on the user population.
Use bulleted lists to communicate points or steps.
Use the active voice rather than passive voice.
Use concrete rather than abstract wording.
Avoid using words or statements that might have
multiple interpretations.
Signal Words
Danger--Indicates immediately hazardous situation
that will result in death or serious injury if not
avoided; use only in extreme situations.
Warning--Indicates a potentially hazardous
situation that may result in death or serious injury
if not avoided.
Caution--Indicates a potentially hazardous
situation that may result in minor or moderate injury.
Pictorials
Use only symbols that have been comprehension-tested
(refer to the following section on evaluation for
a more detailed description).
Font
Use mixed case letters. Avoid using all capitals
except for signal words.
Use san serif fonts (Ariel, Helvetica, etc.) and
larger font size for signal words.
Use serif fonts (Times, Times New Roman, etc.) and
smaller font size for warning messages.
Color
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A red panel with the signal
word "Danger."
An orange panel with signal word "Warning."
A yellow panel with the signal word "Caution."
An alert or signal icon (triangle surrounding
an exclamation point) should be included in
these panels when human injury is a concern.
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Too often, warnings are designed and implemented
without being tested. Print in a font size
large enough so it is readable at a distance
and by older people.
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Evaluation: Testing is Needed to Be Sure
The final step in the design phase is to develop prototypes
of warnings, which then should be evaluated to identify
which one will be used as the final design. All too
often, warnings are designed and implemented without
being tested. There are two major types of testing:
comprehension and behavioral.
Comprehension testing should be conducted on both
textual and pictorial (if included) components. Such
testing focuses on whether receivers understand the
information being conveyed by a warning. With respect
to pictorials, two sets of guidelines are used to
guide comprehension testing: ANSI 1998b and the International
Organization for Standardization (ISO, 1988). The
former requires that 85 percent of individuals will
comprehend the meaning of the given pictorial with
less than 5 percent critical confusions (understanding
the pictorial to mean opposite of its intended message).
ISO, on the other hand, requires a 67 percent comprehension
rate.
Most often, behavioral testing examines behavioral
intentions rather than actual behavioral compliance.
Behavioral intentions are reported actions a person
will take when exposed to a warning, which are typically
measured by a questionnaire. Behavioral compliance
consists of observing a person interacting with a
warning, to determine whether their actions are in
accordance with the warning message. Behavioral compliance
can provide the most valuable information, but it
is often time-intensive and costly.
After conducting the evaluations, the warning prototypes
probably will have to be modified because the warning
design process is iterative by nature. The necessary
changes will be guided by the feedback received during
the usability inspections and testing. After the necessary
changes have been made, the new prototype should be
re-tested. This process should be repeated until the
warning is deemed acceptable.
Conclusions
Designing effective warnings requires careful planning
and familiarity with basic warning design guidelines
and principles. As noted above, testing is a critical
step in the design process. Appropriately implementing
and following the warning design process presented
in this article increases the likelihood an effective
warning will be developed, and hence, fosters safety
in the workplace and reduces work-related injuries.
