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3 THE DEVELOPMENT OF PD

Avoidance of hazards and risk, the top of the hierarchy, should always be considered the first in the practice of OSH. Fundamentally, avoiding a problem rather than accepting it and managing around it, makes good sense from an OSH as well as a business standpoint. Systems are designed and brought into the workplace, bringing with them embedded elements, some of which are hazard‐risks. These embedded hazards are present in the system for its entire lifecycle. When efforts are made to anticipate, identify, assess, and control hazards and their risk during design, the resulting system is improved in a number of ways. This concept is known as PtD.

Prevention through design, PtD as it is known, can be traced back to the 1970s in certain industries including automotive as a result of the newly enacted Occupational Health and Safety Administration (OSHA) safety regulations. In an effort to meet regulations, process engineers began exploring ways of designing in safety to improve machine designs, safeguarding, and noise reduction (6). Efforts to design in safety continued in certain industries, however, inconsistently. Then, in 1994, a Position Paper was released by the American Society of Safety Engineers–American Society of Safety Professionals (ASSE–ASSP now) to promote the gathering of knowledge and applications of “Designing for Safety” as it was originally called. In 1995, the National Safety Council established a 10‐year effort, the Institute for Safety through Design. This Institute fulfilled a need for integrating hazard analysis and risk assessment into the conceptual stages of design with the purpose of avoiding and eliminating hazards and risks. In 1999, the Institute published the landmark book, “Safety through Design” edited by Fred Manuele and Wayne Christensen. It provided real‐life examples from 20 contributing authors of PtD and design safety efforts from various industries and presented the benefits derived. The work and research conducted through the Institute and the National Safety Council were to be the foundation of the current PtD concepts and practices.

In 2007, after the 10‐year National Safety Council effort concluded, leaders at the National Institute for Occupational Safety and Health (NIOSH) invited all stakeholders, including the authors of “Safety through Design,” to continue the effort and join with them in a National Initiative called “PtD” (7). As part of the PtD initiative, over three hundred representatives representing ten different industry sectors met, culminating in “The Plan for the National Initiative” in 2009 (www.cdc.gov/niosh/docs/2011-121). Goals in the plan are organized into education, research, practice, and policy. A progress report was published in 2014, “The State of the National Initiative on PtD” (www.cdc.gov/niosh/docs/2014-123). Other PtD efforts at NIOSH can be found at the PtD website, www.cdc.gov/niosh/topics/ptd.

A key policy advance was the American National Standards Institute (ANSI)/ASSP Z590.3 PtD consensus standard, discussed in detail in the remainder of this chapter. Important policy guidance was also needed in the burgeoning “green” industry. In 2009, NIOSH held a “Making Green Jobs Safe” PtD workshop, where, in his first official speech as OSHA administrator, Dr. David Michaels, asked: “How sustainable is dangerous technology?”

After four years of collaboration with the NIOSH PtD and Construction programs, the U.S. Green Building Council (USGBC) published, in 2015, a Leadership in Energy and Environmental Design (LEED) PtD pilot credit for building certifications (www.usgbc.org/articles/new-leed-pilot-credit-prevention-through-design). The pilot credit, developed in partnership with NIOSH, prompts the use of PtD methods to design out worker hazards for both the construction phase and operations and maintenance phase of a building's life cycle. Similar to the publishing of the ANSI/ASSP Z590.3 PtD Standard, this PtD LEED credit is considered a major strategic advance for PtD, as LEED criteria are used throughout the United States, and around the world.

Returning to the first of the key policy advances for PtD, in 2011, the first U.S. standard to address the need for incorporating safety into design was published – ANSI/ASSP Z590.3‐2011 PtD – Guidelines for Addressing Occupational Hazards and Risks in Design and Redesign Processes standard. ANSI/ASSP Z590.3‐2011 (R2016), or the PtD standard as it is sometimes called, provides guidance for assessing and treating risk throughout the life cycle of a system. Z590.3 provides an operational risk management model that balances environmental, safety, and health goals over the life span of a system as shown in Figure 1.

Workplace systems, facilities, equipment, and products all have a defined life cycle in which risks may change. As shown in Figure 2, these phases, changes, and events of a system's life cycle represent “triggers” for identifying, assessing, and treating risks to achieve and maintain acceptable risk.

As stated in Z590.3, an important goal of the standard is to educate designers, manufacturers, OSH professionals, business leaders, and workers in PtD principles and encourage their application in design and redesign efforts.

An important concept in PtD is the “avoidance” of risk in designs. The ANSI Z590.3 PtD hierarchy of controls model, shown in Figure 3, promotes the use of higher‐level controls – avoidance, elimination, substitution, and engineering – in the design and redesign phases. These higher‐level controls are considered the most effective in reducing risk and more economical than lower‐level controls such as administrative and personal protective equipment (PPE). This concept is logical, however, in practice, few organizations have fully taken advantage of pre‐operational risk management or PtD. More efforts and research are needed to further the practice of PtD.

FIGURE 1 Life‐cycle process reprinted with permission from ANSI/ASSP Z590.3‐2011(R2016).

FIGURE 2 Prevention through design during system's lifecycle (8).

FIGURE 3 ANSI Z590.3‐2011 (R2016) prevention through design risk reduction hierarchy of controls model reprinted with permission.

The objective of operational risk management is to implement appropriate risk reduction plans to reduce risks associated with each decision made to achieve an acceptable risk level. OSH professionals should be able to effectively lead risk assessments, develop appropriate risk reduction strategies, and advise decision‐makers in making appropriate decisions. Risk treatments (i.e. risk controls) are designed to reduce the risk of a hazard's effects and/or reduce the likelihood of its occurrence. A risk treatment plan should include options and alternatives that eliminate the hazard or reduce its risk. To provide OSH professionals a broader range of risk reduction strategies that include “inherently safer design” concepts, the authors have proposed a Hierarchy of Risk Treatment (HoRT) Strategies Hierarchy model illustrated in Figure 4 (9).

The HoRT model includes 10 risk treatment strategies divided into three categories: (i) design, (ii) engineering, and (iii) administrative controls. Of the three categories, design risk treatments are the only measures that are long lasting and resistant to degradation. Hazards that are avoided, eliminated, or reduced through substitution will not change unless the design changes. Engineering and administrative controls are less resilient, effective, or reliable. Engineering controls can be circumvented, degrade over time, and require periodic inspection, testing, service, and repair. The least effective group of controls are administrative measures. Variations in application, quality, and management as well as human error make such measures a less effective and less reliable option (9). Brief descriptions and examples for each risk treatment strategy are presented in Table 1.

FIGURE 4 Hierarchy of risk treatment (HoRT) (9).

Table 1 Brief descriptions and examples for risk treatment strategies.

Strategy	Description	Examples
Avoid	New hazards/risks are intentionally avoided in new designs, and redesigns, additions, and modifications to existing systems and workplaces	New facility avoids falls from heights by designing all working and walking surfaces at the same level
Eliminate	Existing hazards/risks are eliminated or removed from systems/workplaces through redesign	A hazardous chemical process is eliminated from the workplace by redesign of the process or removed from the workplace and isolated away from workers
Substitute	New or existing hazards/risks are intentionally substituted and replaced with less hazardous materials that meet the needs of the system/workplace	A highly hazardous chemical such as pure sulfur dioxide is replaced with a less hazardous chemical such as potassium meta‐bisulfite
Minimize	The amount or quantity of a particular hazard is minimized to a level that presents a lower severity risk	The size and weight of materials are minimized to a level that can be handled easily by workers; the smallest quantity of hazardous materials feasible for the process are used; lower voltage or energy required in system; or reduced operating temperatures and pressures
Simplify	The likelihood of error or occurrence is reduced through simplifying the systems/workplace processes and controls	Reduce unnecessary complexity in controls and displays; reduce the number of steps to complete a critical task; incorporate human factors engineering design into systems to reduce human error potential
Engineer with passive controls	Hazards are controlled and/or contained by passive engineering controls that protect/function without activation	Containment dike around a hazardous material storage tank; fixed/permanent guard on a machine; hard/fixed barriers
Engineer with active controls	Hazards are controlled by active engineering controls that require activation to protect or function	Presence sensing devices on machines; process controls and safety instrumented systems (SISs); automatic fire suppression systems and sprinkler systems
Warn	Awareness device that informs or warns of residual risks by sight, sound, or touch	Forklift backup alarms; perimeter warning tape and signage; highway “rumble strips” to indicate drifting off road
Procedures and training	Hazards are managed by applying work procedures and worker training for safe operation of the system/workplace	Written standard operating procedures and protocols; employee orientation and training; behavior‐based safety efforts
Personal protective equipment	Hazards are managed by donning and wearing protective clothing and equipment to prevent or reduce contact, exposure, and impact or harm from hazards	Respiratory protection; FR/flame resistant clothing; fall protection harness and lanyard

Patty's Industrial Hygiene, Hazard Recognition

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