Occupational Health & Safety

PPE

PPE-volution

By Marc Barrera · January 2007

America's Industrial Revolution and ingenuity brought about many important advances in worker safety and protection.

AT the start of the American Industrial Revolution, worker safety and health were nowhere near the priority they are today. As manufacturing grew, so too did worker injuries and deaths. The idea of safe work grew slowly from a small glimmer to a bright flame inside the collective consciousness of the American workforce.

Although the creation of OSHA regulations was many decades away, the evolution of PPE progressed on its own with the creation of new types of protective devices and advancements in pre-existing devices that are too numerous to list here. Still, much of this early PPE had a major influence on worker safety's advancement and will continue to do so.

Hard-Headed
San Francisco's Golden Gate Bridge, built in 1933, is an excellent early example of PPE's influence on safety. Constructing a cable-suspension bridge that was 4,200 feet long was a task that had not been attempted before, one that presented many hazards. The project's chief engineer, Joseph Strauss, was committed to making its construction as safe as possible.

The bridge's construction played a particularly significant role in the successful development of one form PPE: It was the first major project that required all of its workers to wear hard hats. Although the hard hat was in its infancy at the time, head protection wasn't new; gold miners had learned long before the importance of taking steps to protect against falling debris. Michael Lloyd, head protection manager at Bullard--a company in business since 1898--said many early miners wore bowler hats, which were hard felt hats with rounded crowns. Often dubbed "Iron Hats," these were stuffed with cotton to create a cushioning barrier against blows.

Inspired by the design of his "doughboy" Army helmet, Edward Bullard returned home from World War I and began designing what was to become known as the "hard-boiled hat." The hat was made of layered canvas that was steamed to impregnate it with resin, sewn together, and varnished into its molded shape. Bullard was awarded the patent in 1919. Later that year, the Navy approached Bullard with a request for some sort of head protection for its shipyard workers. The hat's first internal suspension was added to increase its effectiveness, and the product's use quickly spread to lumber workers, utility workers, and construction workers. By the time of the Hoover Dam's construction in 1931, many workers were voluntarily wearing the headgear. Soon after, the Golden Gate Bridge construction provided a true test of the hard hat's protective capability because falling rivets were one of the major dangers during the project.

Other innovations came in the form of different materials. In 1938, Bullard released the first aluminum hard hat. It was more durable and comfortable, but it conducted electricity and did not hold up well to the elements. In the '40s, phenolic hats became available as a predecessor to fiberglass hats. Thermoplastics became the preferred material a decade later for many head protection products; it's still used by many manufacturers today.

In 1953, Bullard introduced the process of injection-molded hats. "Before, [thermoplastic] was kind of laid out on a mold. In the injection-mold process you actually have a closed mold that you pump into. It makes a more consistent helmet and a higher-quality product, which in the long run is also going to be the same thickness all the way through. It's going to be a safer helmet," Lloyd said.

Despite the hard hat's effectiveness and relatively low cost, its use wasn't officially required at most job sites until the passage of the Occupational Safety and Health Act in 1970. OSHA's head protection standard, 1910.135, obligated employees to protect workers and instructed manufacturers and employers to turn to the American National Standards Institute's Z89.1 standard for the appropriate usage guidelines.

Many new materials have since been created, such as the use of General Electric's high-heat-resistant polyphthalate-carbonate resin in firefighters' helmets. New hard hats have been designed that provide side protection, which are designated type 2 hats in ANSI Z89.1. "A hard hat was originally designed to protect if something falls from that sky and hits you in the head," Lloyd said. "But what happens if you run into something? What happens if you bend over and something hits your helmet?"

Because hard hats are a mature market, except for the development of other materials, most innovations will be comfort features and technologies enabling them to withstand different temperature extremes, Lloyd predicted. Easier-to-use designs are appearing that allow users to adjust a hard hat's suspension with one hand. In the last couple of years, manufacturers have come up with different types of vented helmets designed to help workers keep cool. Hats are accessorized with attachable faceshields, visors, and ear muffs, and some have perspiration-absorbing liners. Some come with AM/FM radios, walkie-talkies, and camcorders.

Netting a Safe Return
Although primitive by today's standards, the solution for the problem of falls also was addressed during construction of the Golden Gate Bridge. Three years into the construction, delays had convinced Strauss to invest more than $130,000 (these were Depression-era dollars, remember) on a vast net similar to those used in a circus. Suspended under the bridge, it extended 10 feet wider and 15 feet farther than the bridge itself. This gave workers the confidence to move quickly across the slippery steel construction. There were reports of workers being threatened with immediate dismissal if found purposely diving into the net.

Strauss' net was heralded as a huge success until the morning of Feb. 16, 1937, when the west side of a stripping platform bearing a crew of 11 men broke free from its moorings. After tilting precariously for a moment, the other side broke free and the platform collapsed into the net, which contained two other crew members who were scraping away debris. One platform worker, Tom Casey, managed to jump and grab a bridge beam before the platform fell; he hung there until rescued. The net held the platform and the others for a few seconds before it ripped and fell into the water. Two of the 12 men who fell survived.

Fall arrest devices were used in the early 20th Century by many professionals, although they used rope lanyards made of natural fibers, such as manila hemp, and simple body belts with no shock-absorbing properties. Clarence W. Rose--who early in his career was a window washer--became a pioneer in fall protection when he started the Rose Mfg. Co. in 1934 and began producing safety belts and lanyards for window washers. On Nov. 24, 1959, Rose was awarded a patent for an easy-to-use cable connecter for safety belts that also had some shock-absorbing properties (U.S. Patent 2,914,139). Listed in the patent was a statement that the connector could, among other things, "be adapted to slip somewhat responsive to a sudden jerk as when the safety rope checks the fall of a wearer and thereby eases the shock to the wearer incurred by checking the fall."

Joseph Feldstein, manager of Technical Services at MSA, which purchased the Rose Mfg. Co. in 1996, said the idea of a shock absorber was a major step forward in protecting against the large braking forces generated in arresting falls, especially during Rose's time. "If you can imagine, workers with a simple belt and lanyard arrangement that was common up until that point would be exposed to a fall that could not only damage them internally because of the forces exerted to the soft tissues of the abdomen around the belt, but also you could generate such forces that you could separate the lanyard," he said.

Rose continued to develop his shock-absorbing concept and was awarded several patents for newer and better shock absorbers. Ultimately, his designs influenced the creation of the modern-day shock absorber. Rose also received many other patents related in some way to preventing or protecting workers from falls. An example is the patent for an early "Ladder Climber" harness system (U.S. Patent 2,886,227) that contains two hook lanyards that are both attached to a harness. While ascending or descending, a worker grasps one hook in each hand and secures them over alternating ladder rungs.

Decades later, the industry would see the emergence of locking snap hook connectors and full-body harnesses, both gaining much more acceptance in the 1980s. In 1990, OSHA enacted regulation 1910.66. Craig Firl, product marketing manager in Hardgoods for Capital Safety-USA, said appendix C in this regulation was the key to getting several areas of fall protection technology up to date. "Even though that particular standard at that time allowed for non-locking-type hooks to be used in a fall protection-type system, they recommended the locking type to be used because they were safer hooks and more compatible," Firl said.

Feldstein agreed, adding that the acceptance of the locking snap hook led to the creation of a whole new series of connecting anchorage systems: straps, D-rings, and more. "And that's continued to evolve to its current state, where we now have personalized anchorage connectors for almost every application, whether it's building construction or general industry," he said. Even though body belts were still allowed, Feldstein said appendix C acknowledged that OSHA recognized full-body harnesses as a major innovation in fall arrest. "Belts are still permissible in positioning, but in a fall, you definitely want to be protected by a full-body harness. It distributes the load across your chest and the bony mass of your hip, where your body is most capable of absorbing a blow, and it protects the soft tissue of the abdomen," Feldstein said.

Two years after 1910.66 arrived, the ANSI committee released standard Z359.1, the key fall protection standard in use today. Most notably, it required the use of full-body harnesses and self-locking snap hooks. Firl said this voluntary compliance standard put pressure on OSHA to recognize that its existing standard needed updating and encouraged the completion of another fall protection standard for the construction industry, Subpart M, in 1995. According to this standard, as of Jan. 1, 1998, the use of body belts and non-locking snap hooks was prohibited.

During the '80s, Self-Retracting Lanyards (SRLs) gained in development and use. They had been developed in the 1950s for offshore oil production in the North Sea but quickly became a common component in fall protection systems worldwide. Feldstein said SRLs became so valuable because they allowed workers to be protected along a much greater length of travel, increasing productivity without sacrificing safety. He described a scenario for rail car workers: "Workers could be protected from the ground level and all the way up to the top of the rail car while they were working along the train's length because the SRL could be mounted mobilely overhead. So that afforded a new type of protection for all types of workers in transportation, everything from rail cars, truck load-outs, and air craft maintenance."

Regarding fall protection's future, Firl and Feldstein said they believe comfort will continue to advance. Firl also foresees advances into niche markets with specialized materials and components, similar to the vacuum anchors' progression into the airline industry for maintenance work on aircraft, whose surfaces can't be penetrated with traditional-type anchors. "In the past, a harness was a harness. It didn't really matter if it was for construction, or utility work, or warehousing, it was a harness," he said. "Now, you're starting to see more specialized gear. . . . As an example, in the utility segment, you would see extensively the use of flame-resistant materials . . . because they're concerned about heat resistance; they're concerned about being able to resist arc flash and so forth."

Feldstein said advances in education may eventually eliminate all fall hazards as emphasis moves toward designing fall hazards completely out of a building's construction and future occupancy. "I think you'll see more and more of that as we have seen already in parts of the world, like Europe, where the building codes are forcing the building owners and the designers of new buildings to incorporate means to prevent falls from ever occurring, so you don't need PPE in the future," he said.

Wearable airbags might be a future component of fall protection systems. Peter Simeonov, Ph.D., research safety engineer for NIOSH's Division of Safety, gave a presentation on the technology at the 2006 International Society for Fall Protection Symposium, in which he mentioned two Japanese manufacturers that are actively developing wearable airbag technology that would absorb much of the force from a fall. One example is the "Itsumo" air bag (U.S. Patent 5,937,443), which is designed to quickly inflate and protect the spine, neck, and waist of a worker who is falling. Although the technology will certainly improve in the future, recent tests conducted by the National Institute of Industrial Safety in Japan confirmed Simeonov's opinion that the product does not protect enough to replace all fall protection devices but could be a supplemental option should all other devices fail. "It would probably be very difficult to provide complete protection with such devices because it cannot protect the head sufficiently," he said. "So I look at it as a possible field of improvement for a supplemental protective measure in impact protection and fall protection rather than a complete solution." This technology is also being developed to protect people who are thrown from a motorcycle and elderly people who fall.

A Breath of Fresh Air
During construction of the Golden Gate Bridge, a respiratory problem arose when workers sandblasted steel beams that had arrived rusted. Although respiratory protection did exist, Strauss went to Bullard for a quick solution, and a makeshift respirator was fashioned by attaching a skirt around a hard hat that was fitted with a supplied air hose and used in combination with an abrasive-blasting cape.

Respirators date as far back as the Roman Empire, when animal bladders were used to protect lead miners against inhalation of red oxide. Filtration really began to advance with the discovery of activated carbon's ability to remove organic vapors and gases from the air. One notable pioneer was John Stenhouse, who in 1854 unveiled a "charcoal gas-filter" mask at a meeting of the Society of Arts in London. It was claimed the mask could remove chlorine, hydrogen sulfide, and ammonia from the air. Stenhouse decided not to patent the design and instead made the device available to the public, perhaps to allow for its further development, because many Londoners were then being affected by dangerous exposures of hydrogen sulfide coming from London's drains and sewers.

In 1871, physicist John Tyndall took Stenhouse's mask and added a filter of cotton wool saturated with lime, glycerin, and charcoal, inventing a "fireman's respirator" he unveiled at a meeting at the Royal Society in London in 1874. That same year, Samuel Barton patented a similar device that allowed respiration in atmospheres charged with noxious gases (U.S. Patent 148,868).

Though respiratory protection devices had been used in Europe for many centuries in one form or another by miners exposed to poisonous gases, patents for respirators didn't show up in the United States until 1823. And it would be nearly a century later before the benefits of respirators would gain national attention.

In 1914, African-American inventor Garret A. Morgan was granted a patent for an air-purifying respirator called the "Morgan Safety Hood and Smoke Protector" (U.S. Patent 1,113,675). Morgan's APR was originally designed to help firefighters. It consisted of a canvas hood with two tubes extending down the sides that merged into a single tube at the back. A water-soaked sponge attached to the open end of the tube filtered out smoke. In 1916, there was an explosion at the Cleveland Waterworks. After three previous teams of rescuers had been overcome by gases and had not returned, Morgan, his brother, and two volunteers, all using his respirators, succeeded in entering the gas-filled tunnel under Lake Erie and pulling everyone out. The simple genius of this invention's design was the fact that its breathing tube extended down to the ground, where it drew in air that was free of the dangerous gases that rose to the ceiling. Its success received national press coverage, and Morgan's APR became the foundation for future gas masks that were used by the U.S. Army during World War I to protect soldiers from chemical warfare.

In ensuing decades, respirator facepiece options progressed to include full, half, or quarter facepieces. More pliable materials, such as silicone, were available as alternatives to rigid rubber. John King, technical director at Bullard, said 3M's patented release of its first disposable filtering facepiece had a large effect in the industry. "They got that approved by NIOSH, and that was a major innovation because it reduced the cost of respiratory protection and made it easy to use," he said.

Another significant innovation came in the '70s with the emergence of the Powered Air Purifying Respirator, which employed a blower and filter element inside a helmet. "It gave you portability over having to be tethered to a supplied air line because you had a battery-powered blower inside the helmet," King said. "Also, you had some degree of positive pressure, as opposed to being a negative-pressure device, because you had a blower that was pumping the air through the air-purifying element."

John Hierbaum, product line manager for MSA, said many issues still have to be resolved before PAPR use can be expected to expand in the future. "They're bulky and they're big. You have to charge the batteries, you've got to carry a blower with you, and they're a lot more expensive than just a filter facepiece or negative-pressure respirator," Hierbaum said, adding that in many jobs, such as construction, workers don't need the level of protection PAPRs provide. "You can get away with a dust mask or a cartridge-type respirator because the exposure levels are low and they're not carcinogenic."

King noted one area that will help advance PAPRs' future is the development of breath-responsive technology that senses when it is necessary to speed up or slow down blower power to fit the user's need, thereby preventing the creation of negative pressure by over-breathing the respirator. "Positive pressure gives you more protection than negative pressure, so we're going to see more tendencies toward respirators to deliver positive pressure," he added.

Hierbaum said another possible significant advancement in the future of respiratory protection could be the development of a reliable end-of-service-life indicator on filter cartridges. Currently, manufacturers make available cartridge life expectancy guidelines or online calculators that estimate the life of their cartridges based on use. While helpful, this is subject to a fair amount of user error. "Cartridges are used and overused and abused. The reason being is that sometimes people don't know when to throw them away, or they don't care to learn," said Hierbaum, who feels the main challenge for such an item is reliability. "The reason it's not out is there is a hell of a lot of contaminants that people use respirators for, and trying to make one indicator that's the answer to all the contaminants is pretty difficult."

The Sound of Silence
Just as falling rivets were a hazard to Golden Gate Bridge workers, hazardous noise came from hammering the rivets home. Although the lack of hearing protection regulations made concern over hearing loss largely a non-factor in industry until after World War II, hearing protection has a long history. Bill Sokol, vice president of Strategic Marketing for the Bacou-Dalloz Hearing Safety Group, traces the earliest instance of hearing protection to Homer's Odyssey, where the poet describes beeswax used to stop up sailors' ears and block the seductive call of the Sirens.

Patents for hearing protection devices began to be issued as early as the 19th Century, and by the 1920s, ear plugs were being sold for use in big cities such as New York and Chicago to help residents cope with the incredibly crowded and noisy conditions. Often made from cotton and wax, these early ear plugs were meant to help users sleep rather than protect their hearing. By the 1930s, some manufacturers were advertising their ear plugs to plant owners by offering trial distributions, such as a 1936 ad in this magazine (then titled Industrial Medicine) from New York-based Flents Products Co. Inc. that warned, "Noise takes a steady, invisible toll of employee efficiency. Protect your workers against the nerve-shattering effects of noise and you increase your workers' efficiency, energy and health."

In 1969, before the formation of OSHA, the U.S. Department of Labor incorporated the "Walsh-Healey Noise Standard" under the authority of the Walsh-Healey Public Contracts Act, which applied to all federal contract work. Along with other consensus standards, it became OSHA's noise standard in 1971. Because of industry pressure for clarification of its "continuing, effective hearing conservation program" requirement, the standard was nearly amended in 1981, but a reshuffle of OSHA management delayed it a couple of years. The Hearing Conservation Amendment (29 CFR 1910.95) was finally enacted in 1983. Although it forced industry to conduct performance tests on all hearing devices in order to comply with noise reduction ratings, responsibility for providing NRR guidance fell to the Environmental Protection Agency.

Ear muffs had a simpler, more practical purpose at the start that was not related to prevention of hearing loss. At the age of 15, Chester Greenwood invented the "Greenwood Champion Ear Protector" and was awarded a patent on March 13, 1877 (U.S. Patent 188,292). Greenwood constructed his device to protect his sensitive ears from the cold weather. With the help of his grandmother's stitching, he fashioned the muffs from beaver fur, velvet, and farm wire.

Muffs developed into hearing protection devices during World War II. Also, said Sokol, the growing assortment of foam materials during the mid-20th Century led to a wider use of hearing protection devices, particularly with ear plugs. "Foam ear plugs came into their own around the '60s through the '80s, where the PVC, barrel-shaped ear plug was really capturing most of the market and dominating it," he said. "Then, about 15 to 20 years ago, polyurethane foam began to emerge as probably the preferred material for ear plugs. It's a little bit softer, easier to work with, more able to contour into different shapes, and it has a smoother skin."

Today, ear plugs dominate the global hearing protection market as new materials are routinely introduced that protect better and are more economical. An example is thermal plastic elastomer, a compound that responds to body heat inside the ear canal to form a better fit. There are materials that distort human speech less, allowing people to converse over machine noise without removing their ear plugs. Other advances in hearing technology have led to better fit testing devices, such as tiny microphones that can be inserted into ear plugs and ear muffs to measure noise exposure inside the ear canal and alert employers when a worker has reached a preset noise exposure limit.

Despite so many advances, hearing loss continues to rise among U.S. workers. Sokol predicted the problem will continue to grow in the future unless manufacturing employers take new approaches. "To me, one of the more interesting frontiers of hearing protection lies not within the ears, but more between the ears of the people who are working in noise environments," he said. "We believe that the next frontier is the human side of this issue. Why don't people take hearing protection seriously? Why is someone who wears their protective eyewear or gloves every day on the job resistant to the idea that they can lose their hearing in the same environment?"

Part of the solution is to incorporate hearing protection completely into workers' lives, on and off the job, he said. "Hearing protection isn't something that you can punch a clock on. To really be effective, employers are going to have to look beyond what happens for an eight-hour shift. They're going to have to look at how their employees are protecting their hearing around the clock," he said.

The Big Picture
Sokol's suggestion may be true for the future of all PPE categories, and it is being acknowledged by many employers and manufacturers. To reduce injuries and downtime, some allow their workers to take PPE home to use in their personal lives, thus preventing accidents suffered by employees who may be weekend warriors, amateur carpenters, or mechanical enthusiasts. Others have gone as far as to give out safety videos that cover safety concerns of the employee's family.

Regardless how much promise PPE holds in the future, its advancement and value will be limited by the extent to which industry takes steps to foster a complete "safety aware" environment that goes beyond the end of the workday. Such an environment includes pushing current and future generations to be safety conscious and striving to design out hazards to the greatest extent possible. If our culture's safety consciousness progresses down this road, the future looks promising.

This article appeared in the January 2007 issue of Occupational Health & Safety.

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Preventing 'Shell' Shock
Do you think wearing a hard hat looks silly? It doesn't when you consider its predecessor. Michael Lloyd, head protection product manager at Bullard, said the conventional wisdom in the head protection industry is that the earliest form of head protection probably occurred when the first cavemen strapped a turtle shell to his head.

Thus, it makes sense that a club founded in 1946 to promote the use of hard hats by C. R. "Rusty" Rustemeyer, safety director of Canadian Forest Products Ltd., would be called "The Turtle Club." Four years after its founding, sponsorship of the club was handed over to Bullard, originator of the hard hat, which sponsors it to this day.

Acceptance into the club is simple: Applicants must have their supervisors or company safety directors submit the story of how a hard hat saved their lives or prevented a serious injury. Once accepted, these lifelong members receive a membership certificate, a membership card, a new hard hat, a Turtle Club pin, and a Turtle Club decal. Members must follow the club pledge to "Practice safety, wear head protection when necessary, and to conscientiously encourage others to do so."

The club reached its heyday in the '70s, when membership reached 100,000 living members. Although membership has dwindled some, as many as 50 new members are added each year. "It's still a good program, because the whole concept is if a hard hat saved your life, you want to be able to tell other people about that. The most difficult thing with head protection is getting people to wear it," Lloyd said.

For more information, including a downloadable application, visit www.bullard.com/Industrial/turtle_club.shtml.

About the author

Marc Barrera
Marc Barrera is Associate Editor of Occupational Health & Safety.