According to the latest National Safety Council Report on Injuries in America, 3.8 million American workers suffered disabling injuries from unintentional causes on the job in 1998. There was a fatal injury every 103 minutes and a disabling injury every 8 seconds. Medical expenses, property damages, employer costs, fire losses and other expenses from unintended events cost an estimated $125.1 billion that year.
In a survey of more than 16 million production employees, OSHA determined that 40 percent of workers were at risk for serious hand injuries. In 1994, OSHA mandated that every employer assess the hazards associated with the performance of every job. The hazard assessment has to be kept on file, and employees must be supplied with the correct personal protective equipment (PPE) and trained to correctly use it. The employees have a “Right-to-Know” the hazards.
Hand-related hazards
Hand injuries account for a large percentage of injuries that are classified as preventable. In an OSHA survey of 1.8 million disabling occupational injuries, 320,000 were hand and finger related. With the correct protection measures, either through job modification or by using the correct hand protection, these injuries can be minimized or eliminated.
There are many different types of hand injuries. These injuries can be categorized as resulting from physical, biological or chemical hazards. Following is a discussion of each, with recommendations for specifying the correct hand protection.
Physical hazards
Preventable injuries from physical hazards include cuts and lacerations, abrasions, puncture wounds, burns from heat or cold, snags and pinches. With the proper glove, these injuries are largely preventable. For example, new advances in polymer and fiber technology have resulted in a new category of cut and heat resistant fibers such as Kevlar, Spectra and Certran X. Gloves manufactured from these fibers provide superior protection from cuts and lacerations, compared to cotton, leather or synthetic yarn gloves.
Various coatings are often applied to gloves for additional protection. For abrasion injury prevention, work gloves with a heavy coat of a polymer such as nitrile, natural rubber, neoprene or PVC can provide the needed toughness to prevent injuries resulting from scrapes. These supported gloves have a textile substrate that gives reinforcement to the polymer coating and are ideal for protecting hands from abrasion injuries.
Lightly coated gloves do not offer quite as much protection from abrasion injuries, but do provide more flexibility and touch sensitivity. They consist of a knitted or woven base glove coated with a polymer such as nitrile, natural rubber, polyurethane or PVC. Polymer-coated gloves also provide excellent puncture resistance from nails and nail-like objects.
Polymer-coated gloves are excellent protection for the hazards of snags or pinches. Some gloves have a special safety cuff that allows the wearer to take the glove off quickly if it gets caught in moving equipment or is snagged in such a way that the hand could get drawn into moving parts. Different cuffs on gloves are designed to meet the needs of the wearer. For instance, knitted wrists on gloves are warm and prevent small particles such as wood or metal shavings from going down into the gloves and irritating the hands. Safety cuffs are designed for quickly doffing the gloves in case of hand danger. Gauntlet cuffs come in all different lengths, and are designed to protect from chemical splashes or from contact with substances that could harm the wrist and arm.
Biological hazards
Selecting the correct glove for handling biological hazards requires that you consider several factors. Gloves must first meet the basic criteria of providing good manual dexterity so workers can effectively perform the many functions associated with handling biological substances. They also should provide protection from chemicals and disinfectants used in such applications.
Finally, the gloves themselves must not aggravate allergies, such as latex allergy reactions. Gloves, one of the most important items for protection from biological hazards, must be comfortable. They must also possess excellent barrier integrity and maintain that integrity under strenuous conditions.
Wearing the proper hand protection can minimize exposure to bloodborne pathogens. Medical and industrial gloves are both used where there is a possibility of exposure to biological hazards in manufacturing operation. They are also used in applications such as food processing, where biological hazards must be kept from traveling from workers’ hands into the products.
Chemical hazards
Human skin is a well-designed organ that is an excellent barrier to most agents. However, skin can be seriously injured by local chemical exposure, and the skin’s protective ability can be compromised, allowing ingestion of toxic chemicals. Chemicals can cause excessive drying and defatting of the skin, chemical burns, irritation and sensitization. Using the correct chemical-resistant glove can effectively reduce injuries from localized exposure.
Skin does not provide a barrier from some chemicals. Exposure to these chemicals can cause systemic injuries if the chemical is absorbed into the bloodstream. Once it’s in the bloodstream, it can migrate directly to a body organ or system such as the central nervous system, immune system or reproductive system and cause a toxic effect. It also might be carcinogenic, mutagenic or teratogenic in acute or chronic sub-acute exposures.
Although most toxicology data is based on oral or inhalation exposure routes, many chemicals can be absorbed through intact skin and enter the bloodstream. Therefore, the skin route is important and should not be neglected. By the same token, gloves usually are only part of the answer when it comes to PPE use. Protecting hands from a chemical while inhaling large amounts of it would be self-defeating. But, for many chemicals, exposure by the dermal route is the only route of exposure that occurs.
Not all chemicals are this toxic. Some chemicals are not acutely toxic at all. However, even non-acutely toxic chemicals can have medium or long-term toxic effects that can be avoided by using the correct PPE, which should always include gloves. It is important to know what chemicals are in the workplace and take appropriate measures to avoid all exposures to toxic chemicals.
Because it is essential to the health and well-being of employees that correct gloves are worn whenever the potential for exposure to a hazardous chemical exists, selecting the correct gloves is important. However, selecting the correct gloves to protect workers from chemical exposures can be confusing. Glove specification should be done after careful evaluation of the hazards and glove protection characteristics. Most chemical protective clothing manufacturers provide data on the chemical resistance properties of their products, derived from standardized testing designed by the American Society for Testing and Materials (ASTM).
Glove testing
The most common ASTM method for reporting chemical resistance data for gloves and other chemical resistant garments is the ASTM F-739 test method. This involves total immersion of the protective garment in the test chemical. The test method simulates the worst kind of exposure to a chemical: eight hours of constant, total immersion in the chemical. The resulting permeation data includes breakthrough time, permeation rates and the minimum detection limit of the analytical system.
The breakthrough time is expressed as the number of minutes that elapse between the time the glove material is immersed in the test chemical and the time the chemical is first detected on the inside of the glove. Breakthrough time is easy to understand. The time in minutes tells you how long you can wear a pair of gloves until it is time to change to a new pair.
The permeation rate is not as easily understood. It is the amount or concentration of chemical that permeates, or passes through at a molecular level, a section of glove material over time. It is expressed in micrograms (ug) per centimeter squared per minute. The ASTM standard specifies that permeation data be normalized so that the breakthrough time is reached when the permeation rate reaches 0.1 ug/cm2/min.
Finally, the minimum detection limit is a measurement of the sensitivity of the analytical system. It is measured using a gas chromatograph, pH meter, mass spectrograph, HPLC detector or other instrument, depending on the test method used. This limit, expressed in parts per million, is the lowest level the instrument can detect. A lower number indicates a more sensitive analytical test, which yields more reliable test data.
Glove selection
Chemical resistance data is presented in a number of ways. Manufacturers use this data to help industrial hygienists determine the safest gloves for chemical exposure protection. Wall charts, computer databases or booklets contain selection data, which is usually color-coded to indicate the correct and safest gloves for specific uses.
Protecting workers’ health is the goal of everyone involved in occupational health and industrial hygiene. Using the correct hand protection can significantly reduce or eliminate the potential injuries and long-term debilitating consequences of exposure to physical risks, biological hazards and toxic chemicals in the workplace. Choosing the correct gloves for working with these hazards can be a formidable task. However, with the latest advancements in testing technology and the wealth of information available via the Internet, the correct selection of gloves is manageable.
Photo: Best Manufacturing Co.