When it comes to safety footwear, one size does not fit all. Just as with other types of personal protective equipment (PPE), many work environments and hazards require specific types of footwear if workers are to be properly protected.
So how does a worker put his best foot forward when wearing safety shoes? For starters, an employer should do a hazard assessment of the work environment to determine when and how employees are exposed to foot injury hazards and how to protect them. The assessment is an important element of a PPE program because it produces information needed to select the appropriate footwear.
OSHA's foot protection standard, 29 CFR 1910.136, states that employees must wear protective footwear when working in areas where there is a potential for injury to the feet from falling or rolling objects, objects piercing the sole of the foot or exposed electrical hazards.
What the standard does not specify is quality of footwear. "You get what you pay for" certainly holds true when purchasing safety shoes or boots, said John Klein, merchandising director of Red Wing Shoe Co.
"You're better off spending a little more for footwear and getting what you need," Klein said. "If you spend too little and get an unsafe shoe, you've wasted your money."
A basic element of any quality safety footwear is a steel toe, sometimes called a steel cap. The cap should cover the whole length of the toes from the tips to beyond the natural bend of the foot.
Some workers may falsely believe that wearing a steel-toed shoe is all that is needed to provide foot protection. Unfortunately, they have neglected to take into account other factors in selecting proper safety footwear, such as nonslip and puncture-resistant soles, metatarsal protection and boot material that is designed for electrical or chemical hazards.
Protective footwear must comply with American National Standards Institute's (ANSI) standard Z41-1991. ANSI Z41 separates safety footwear into six categories: impact- and compression-resistant, metatarsal, puncture-resistant, electrical hazard, electrostatic dissipative and conductive.
1. Impact- and compression-resistant footwear uses a steel or nonmetallic toe cap to protect against falling objects or crushing from heavy, rolling objects. Most any industrial work situation calls for steel-toed shoes.
Some safety footwear companies do not sell shoes or boots that will not meet or exceed Z41's Class 75 test standard. Class 75 is a measure of foot-pounds the toe cap will resist while retaining acceptable clearance when a 50-pound weight is dropped from 18 inches onto the protective cap or under a 2,500-pound test load for compression.
2. Metatarsal shoes are designed to prevent or reduce injuries when the metatarsal (upper foot) and toe areas are exposed to "drop" hazards. Metatarsal guards can be internal or external. This type of footwear should be worn on jobs involving a fork lift or where workers carry heavy objects that could be dropped on their feet, such as in the steel industry.
Metatarsal footwear's drawback is that it can be cumbersome, said Don Stella, vice president of marketing for Iron Age Corp., a maker of safety footwear. "The employee isn't so happy about wearing it because he can't wear it home or off the job," said Stella, adding that some of the bulkiness can be alleviated with an internal guard.
3. Puncture-resistant footwear should conform to a set of ANSI standards that, when met, reduce the possibility of puncture wounds to the soles of the feet by objects such as nails, glass or sharp metal that could penetrate the soles of footwear. The footwear should have reinforced, flexible metal soles or inner shoes, assuming there is no risk of electrical contact.
Construction sites are a prime location for this type of footwear, which also is worn in glass factories. Stella contends that this type of footwear should be mandated for the construction industry, but OSHA only recommends its use, leaving the decision up to the employer.
4. Electrical hazard (EH) shoes are nonconductive and designed to reduce the potential for electric shock when the soles are exposed to open circuits of 600 volts or less under dry conditions. Work situations where this footwear is appropriate include the presence of live electrical conductors and construction worksites.
Insulating qualities may be compromised if the shoe is wet, the rubber sole is worn through or metal particles are embedded in the sole or heel. EH shoes are not intended for use in explosive or hazardous locations where conductive footwear is required.
5. Electrostatic dissipative (ED) footwear reduces static electricity by conducting a charge from the body to the ground, maintaining 106 to 109 ohms level of electrical resistance under test procedures. These shoes protect the wearer from electrical hazards due to excessively low footwear resistance. This type of shoe should be worn in the presence of flammable or explosive materials or when handling sensitive electronic equipment.
6. Conductive shoes are designed to minimize static electricity, thus reducing the possibility of ignition of volatile chemicals or explosives, such as at gunpowder factories and printing plants. These shoes, which discharge static electricity from the wearer's body into grounded floors, are not to be worn near electrical hazards.
Conductive footwear should be worn only for the specific task(s) for which it is designed and should be removed at task completion and not used as general-purpose footwear. This type of shoe must not be used by employees working near exposed and energized electrical circuits.
Employees must avoid wearing 100 percent silk, wool or nylon hose or socks with conductive shoes. Foot powders must be avoided because they are insulators and interfere with electrical conductivity.
Some work situations may call for footwear that falls into more than one category. For example, proper boots for mining, heavy manufacturing, heavy construction, forestry, demolition and hydroblasting have extra heel protection, steel-toe and metatarsal guards, steel midsoles and outsole tread patterns for traction and stability in a variety of outdoor and indoor working conditions.
Protective footwear can meet all requirements of the ANSI standard or specific elements of it. A steel-toed work boot that meets the impact and compression requirements of the ANSI standard may not provide protection for metatarsal, electrical or penetration hazards. All footwear manufactured to ANSI specifications will be marked with the specific portion of the standard with which it complies.
When matching safety footwear to a specific environment or hazard, other factors include traction, chemical exposure, cold and heat.
Because there are no federal regulations dealing specifically with slip-resistant footwear, there is no federal testing to ensure slip resistance.
"The traction aspect is probably the last great area of footwear that hasn't been addressed universally by footwear manufacturers," said Jonathan Bell, vice president of operations for Jordan David. "Part of that has to do with the fact that OSHA has no specific regulations dealing with slips and falls. Anything in this category falls under a general hazard guideline."
As a result, buyers should beware, said Matthew Smith, executive vice president of Shoes for Crews, manufacturer of slip-resistant footwear in the workplace. Everyday, rubber-soled shoes and most "slip-resistant" shoes will not adequately protect employees on slippery surfaces, Smith contends.
"The problem that most of the safety managers out there face is that there are a lot of shoe companies who have soles that have the words 'slip-resistant' on them, but they don't work," he said. "It's left up to trial and error."
John Cockrell agrees. Safety professionals should verify manufacturers' slip-resistance claims through referrals from other companies, from shoemakers' references or by testing in a laboratory, said Cockrell, who has a Ph.D. in physical chemistry and is owner of SKL Laboratories in Greensboro, N.C. He tests shoes and flooring materials for slip-resistance for about 50 major corporations.
"If an indoor, hard surface is covered with oil, animal fat or water, there is nothing to get a grip on physically," he said. "The grip will come from microscopic properties of the shoe's outsole. That's why the vast majority of footwear does nothing to prevent slips."
The best way to ensure that a shoe will be slip-resistant for a particular work environment is to have it tested in a laboratory, said Cockrell, who has sought solutions to slips and falls for nearly 30 years. The only test he has found that provides reasonably meaningful information on footwear and floors under worksite-specific slippery conditions is ASTM F16-77.
The F16-77 test will determine if a shoe will meet a 0.25 slip-resistance rating. This minimum acceptable rating measures the horizontal-to-vertical force exerted when the average person puts down his foot.
A factory might need a variety of styles for different work applications, but the floor is the same throughout the plant. Thus, a slip-resistant sole's grip pattern should be the same for all shoe styles, Smith said.
Sole compounds for slip-resistant footwear include rubber-based, polyurethane and polyvinyl chloride (PVC). Rubber soles usually are the best for slip resistance, Smith said.
Chemical-resistant footwear should be worn in areas with potential chemical or corrosive splashes. Unfortunately, there are more chemical compounds than types of shoes, and matching footwear material to a chemical hazard can be a challenge.
One way to determine the proper chemical-resistant shoe or boot is to check the worksite's material safety data sheets to match footwear with individual chemicals. Even that may not be good enough, said Arlen Stensrud of Norcross Safety Products, a maker of boots for chemical and weather environments.
Generally, there are three types of chemical-resistant footwear material: rubber, neoprene or PVC. Seek a chemical resistance comparison guide to find out which one is best for a chemical, said Stensrud, but do not rely on it solely. The best way to make sure a particular material will work in a specific chemical environment, he noted, is to have the footwear tested.
"If there is a hazardous chemical where there is concern about penetration or permeation, it should be tested specifically," Stensrud said. "It's not tremendously expensive and is easily accomplished. Serious decisions should not be made on the basis of the chemical guide."
General applications for the three chemical boot materials:
1. Rubber is suitable for some chemical environments and is rated excellent for many acids and ammonias.
2. Neoprene, lighter in weight than rubber, is rated excellent for most acids, oils, petroleums and many other chemicals. This compound can be used in environments where rubber will not work: meat and poultry processing, petrochemical, agrichemical, oil drilling and refining, dairy and food processing, fishing, breweries and bottling, farming and waste disposal.
"Blood and animal fats are serious enemies to rubber and would deteriorate the boot very quickly," Stensrud said. "Neoprene has tremendous resistance to attack by blood and animal fats and also has tremendous resistance properties to petroleum and petrochemical products."
3. PVC is rated excellent for some acids and some oils. Its compounding is relatively convenient in determining blends to resist specific chemicals, Stensrud said.
Norcross's PVC products range from general industrial applications with no serious chemicals, to moderate blends to resist chemicals in poultry or animal waste environments, to serious compounds for hazmat technicians, site remediation and emergency responders. The latter meets the National Fire Protection Association (NFPA) 1991 chemical permeation-resistant and flame-resistant requirements. It is permeation tested to resist NFPA 1991's list of 21 challenge chemicals.
When working in conditions colder than minus 10, workers should wear arctic footwear, not typical steel-toe safety shoes. Generally, such cold temperatures present more of a risk to feet than a potential crushing hazard.
When choosing the appropriate footwear for cold-environment applications, a boot's warmth factor should be considered, said Dave Markgraff, who heads up product development of safety footwear for LaCrosse Footwear. The company, known for specializing in cold-weather and outdoor footwear, has expanded into industrial-grade leather work boots.
Elements that affect the warmth factor:
- Make sure the boot has a good-quality insulation, which will not lose its bulk. Compressed insulation loses its insulating value. Many name-brand insulations are adequate, Markgraff said. Most cold-environment boots have between 200 and 1,000 grams of insulation.
- The shoe should retain its insulating value if it becomes wet, damp or moist.
- Use the correct type of sock and a polypropylene liner. Socks should be made of wool, because cotton becomes wet more quickly. "A wet foot is a cold foot," Markgraff said. If insulation is of good quality, the feet will perspire.
Target applications for cold-environment footwear include railroads, waste management, cold storage in food processing and outdoor municipal workers.
Because insulation can make cold-weather footwear heavy, seek a lighter boot. All-rubber bottoms are heavy, so footwear that combines rubber with a lighter material, such as polyurethane, will reduce the boot's weight.
"Workers wear them for eight hours or more a day," Markgraff said, "so weight is very critical."
A frequent partner of cold weather is ice. Getting a grip on this frozen hazard takes more than wearing slip-resistant and cold-weather footwear, said Bell of Jordan David, a manufacturer of over-the-shoe, high-traction footwear for ice, snow and other weather conditions.
When trying to prevent slips and falls, especially in outdoor situations, Bell lists two main goals: increase traction as much as possible in areas that may cause accidents, such as ice, snow, oil or grease; and create the ability to wear footwear all the time. Workers may tend to leave on footwear that is inadequate for certain slick situations because of the hassle of changing their shoes or boots.
"Conventional wisdom is that if I have workers slipping and falling on ice, I need to put an aggressive spiked or studded product on the bottom of footwear," he said. "However, what tends to get overlooked is that employees will not be walking on those surfaces all day. They also will be faced with a lot of clean surfaces. The problem with conventional, aggressive footwear is they will help you on ice or snow but are not very safe for clean conditions."
To increase ice traction as much as possible without hindering a worker's walking ability in normal situations, Bell suggests wearing footwear with a sandpaper-like grit texture. This type of surface will increase traction beyond typical rubber soles and can be worn in normal conditions.
"It ends up being a bit of a compromise," Bell admits. "In most cases, this type of technology ended up being the best solution. The reality is that nobody wants to put something on and take it off several times during the day."
Ice is not a problem for workers in foundries, steel mills, food processing plants with high-heat cooking, facilities with heated chemicals or any manufacturing process that includes hot conditions. What these workers need is a boot that will withstand extremely high temperatures and can be taken off quickly if a spill occurs.
The first ingredient to look for in heat-resistant footwear is leather materials, which provide the best protection against heat, said Jim Falcinelli, marketing director of Hy-Test Protective Footwear, a division of Wolverine Footwear Group.
Falcinelli considers pigskin leather to be the best choice. Sometimes called "inferno leather," pigskin is more fire retardant than other leather. "Pigskin is extremely sturdy," he said. "We think it's probably the best product out there."
Hy-Test had a pigskin-leather work shoe dipped in a vat of molten coke at 2,800 degrees. "When we pulled it out, it was still a semblance of a shoe," Falcinelli said. "It was burned up, but it had an outsole and had its sides in place."
When selecting heat-resistant footwear, there are proper boots for specific work environments. For example, foundry shoes protect the feet of workers handling or pouring molten metal. They are made so that hot metal cannot lodge in crevices made by eyelets, tongues or other parts.
To maintain resistance to slips, heat and chemicals, outsoles of heat-resistant footwear should be made of a durable rubber combination or a similar product. Make sure the boots have heat-resistant thread and laces.
"The key is getting out of the boots as fast as you can when you're splashed. You want a shoe that has a speed-lace system," Falcinelli said of pegs that laces go around. Shoes with elastic side panels, such as a molder's shoe, can be removed even more quickly.
A Sure Fit
Once the proper footwear is determined for a particular work environment or hazard, the job is almost done. All that remains is to find a quality shoe and make sure it fits. Footwear can be purchased at a safety shoe retail outlet, from a "shoemobile" that comes to a worksite or through a catalog.
Red Wing's Klein offers guidelines to ensure that a shoe has the proper fit:
- Check for quality materials and construction;
- Use the fitting process to determine correct size, remembering to measure both feet;
- Walk in the shoe and make sure it fits comfortably and adjusts to the foot, with little "break-in" time needed;
- Make sure there is sufficient foot clearance at the steel toe; and
- Ensure that the shoe fits the foot's arch from heel to ball, which helps provide appropriate toe room.
Klein offers a rule of thumb on eyelet spacing: There should be about a finger's width between the eyelet rows, and spacing should be even up and down the instep. "You don't want them too far apart or too close together," he said. One way to tell if the eyelet spacing is incorrect is excessive wrinkling of the boot's vamp, which covers the instep and may extend over the toes.
Ultimately, if the shoe doesn't fit comfortably, the worker could face an unsafe situation, Klein said. "If you're not comfortable, it makes you pay attention to your feet instead of paying attention to what you're doing," he said. "The last thing that an employer who has a safety foot program in place would want is for people to not be willing to wear their safety shoes."