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MANUFACTURING

Selecting and Using Protective Gloves: An Overview of the Critical Issues

In the medical device and diagnostic industry, gloves routinely serve a dual purpose: protection of the employees and of the products they manufacture. Glove selection must not only be based on their ability to protect employees from processing agents used in manufacturing and microorganisms in laboratory environments, but the choice must also take into account the very real problem of potential reactions related to wearing the gloves themselves. In addition, the chosen gloves must protect work-in-progress from particles, skin oils, extractable chemicals, microorganisms, endotoxins, and any other substances defined as contaminants by product requirements; they must not, themselves, contribute such contaminants to the product. And, finally, to maintain their role as a safeguard throughout their time in use, gloves must be durable. This article reviews the key criteria for the selection of gloves for manufacturing personnel and addresses concerns related to their use and disposal. Also discussed is the real concern that glove use may affect product performance.

GLOVES AND THE EMPLOYEE

The importance of fit in glove selection depends on the task being performed. Factors to consider when evaluating gloves include the following:

• Grip. The evaluation of a glove's gripping potential should incorporate actual or simulated work conditions, such as wet or dry, hot or cold; actual materials handled (e.g., metal, glass, plastic); and processing aids used (e.g., solvents, lubricants, alcohols). A slippery glove leads to wasted time recovering dropped parts and increased employee frustration as workers physically strain to fight the slick exterior. Any savings realized by buying low-quality gloves will be offset by the financial impact of scrap from suboptimally assembled and broken parts.
• Style. The choice between hand-specific and ambidextrous styles should be based on the application. Long-term assembly of intricate pieces often requires the fit and comfort of an anatomically designed hand- specific glove. If work procedures are less tedious or glove removal frequent, an ambidextrous style may be adequate.
• Fit. Baggy gloves can cause wearers to execute procedures awkwardly. If infectious agents or hazardous chemicals are used, any accidental spills can put staff at personal risk. Gloves should conform to the hands yet allow ease of movement (low modulus) to minimize fatigue.
• Cuff beading. A beaded cuff can facilitate the removal of gloves from their packaging and make donning easier. Beading also seems to improve fit, reduce cuff roll-down, and provide resistance against drips from processing fluids.
• Durability. Gloves are worn in the manufacturing environment to protect the product from contaminants generated or spread by employees and to protect the employees from potentially harmful solutions or substances. When a glove tears, both functions are compromised. Therefore, it is critical to choose glove materials carefully. Vinyl, for instance, does not have the strength, elongation potential, or flexibility of latex; it breaks rather than gives. This weakness is apparent at the microscopic and macroscopic levels, with tears occurring most notably between fingers and at finger tips during strenuous, friction-creating, and torquing manipulations. During the glove evaluation period, gloves should be worn while simulating routine tasks. After each task is accomplished, the gloves should be filled with water and observed for leaks.
• Lotion compatibility. Most lotions should not be worn under gloves. Those that contain oil (mineral, jojoba, coconut, or palm), petroleum (gels and salves), or lanolin degrade latex and vinyl gloves, compromising barrier integrity.¹ Although a hand-care regimen incorporating these products is encouraged away from the workplace, only compatible lotions should be worn under gloves. Alternatives for use with gloves include lotions formulated with a water, glycerin, or other nonoil base.

To assess the potential degradative properties of a particular lotion, the following simple experiment may be performed. Cut two equal 0.25- to 2-in. strips from the palm or back surface of a glove, and then stretch and secure the strips to approximately 3 times their length. Coat one with the lotion in question, leaving the other uncoated as a control. After 30 minutes, release the strips and place them side by side. If the lotion-treated sample has enlarged either in length or width, and breaks more easily than the control, the material's mechanical stability has been degraded and the lotion is unacceptable.

Chemical compatibility. Gloves should also be evaluated for chemical compatibility with the various solutions that the employees will handle. Evaluations should be performed with the correct chemical concentration, contact (splash or immersion), and length of exposure to ensure relevancy. Indicators of degradation include glove softening, tackiness, brittleness, finger elongation (creep), increased transparency, loss of strength, and loss of elasticity. (Hazardous chemicals require sophisticated methods of permeation analysis, and such tests should only be undertaken by individuals trained for such procedures.) If the glove degrades quickly during routine chemical contact, it will be necessary for workers to change gloves frequently, wear double gloves, decrease chemical contact time, or choose a different glove material.

Staining and discoloration. A discolored glove may or may not be a symptom of glove degradation. Most amber or brown discoloration that is apparent when gloves are removed from their container is a result of overchlorination, excessive heat, overdrying, or contact with copper, brass, iron, or other interactive metals during manufacturing. Such "browning" may or may not indicate a loss of material strength. A variation in the intensity of yellow from one natural rubber glove to another may be a function of the trees used in the respective batch of latex or a very mild case of the browning detailed above. Translucency is caused by insufficient leaching or an excessive use of defoaming agents, emulsifiers, or surfactants during glove manufacture.

Hazing or whitish regions on unused gloves indicate areas of ozone attack. Ozone is created by energy-generating sources such as fluorescent and ultraviolet lights, x-ray machines, heavy-duty fans, and similar equipment. In its attempt to become more stable, ozone breaks the chemical bonds between elastomer chains in latex and most synthetic gloves, leaving the material weaker. This activity begins in creases and folds where the glove material is most stressed, resulting in a line of holes or cracks. Ozone will attack only unwrapped gloves and those enclosed in packages containing excessive amounts of air (available oxygen); therefore, unless the glove manufacturer erred significantly in the addition of antiozonates or exposed the gloves to ozone prior to packaging, this phenomenon can largely be controlled in-house by paying careful attention to glove storage conditions.

If discoloration occurs during use, it is termed staining and may be caused by chemicals from the glove reacting with chemicals secreted by the wearer. For example, carbamate, the least sensitizing of the accelerators used in latex processing, reacts with lactic and uric acid from human perspiration to cause an amber or brown stain. Nicotine from the skin of smokers turns gloves brown, as do copper and iron, excreted to varying degrees through the skin by healthy individuals. Some illnesses and the use of specific medications may also result in glove staining. Gloves with color additives may mask much of the discoloration.

EMPLOYEE REACTIONS

Because attention to employee safety is essential for any company, the potential physiological reactions associated with the use of gloves are a serious concern. Such reactions can affect an employee's comfort, job performance, morale, and future. Careers can be threatened if individuals develop a potentially life-threatening form of allergic sensitivity to their gloves.² Glove-associated reactions can have a significant financial impact, including costs of reduced output, sick leave, medical treatment, temporary or permanent employee replacement, retraining affected employees for work in other areas, and workers' compensation. Though it is currently more of an issue in health-care practice than in industry, litigation for lost earning potential is also a possibility. To effectively address the issue of glove-associated reactions, companies must become aware of symptoms, isolate causative agents, promote employee recovery, and institute preventive measures.

Although there are only three primary reactions associated with the use of gloves, the multitude of terms used to identify them can often be confusing. They can be summarized as follows:

• Irritation--irritant contact dermatitis, nonallergic contact dermatitis.
• Allergic contact dermatitis--delayed-type hypersensitivity, Type IV hypersensitivity, chemical allergy.
• Immediate-type hypersensitivity--Type I hypersensitivity, protein allergy, urticaria, asthma, anaphylaxis.

The three reactions can be distinguished by their clinical features and the agents that cause them.

Irritation. Irritation is a nonallergic condition to which all individuals are susceptible. The first symptom to appear is usually redness, accompanied by itching or burning of the affected area. A rash may develop after repeated or prolonged contact with the source of irritation. More-intense symptoms appear where the glove is particularly tight or imparts repetitive friction, such as at the knuckles, on the back of the hands, or at the wrists. Extensive exposure leads to the onset of chronic symptoms characterized by dry, thickened skin; cracking; and papules (small, hard, raised bumps). Symptoms may occur within minutes or hours after exposure to irritants, never spreading beyond the contact area.

Irritation can be caused by either synthetic or natural rubber latex materials, which contain many of the same chemical additives. The inclusion of large amounts of additives or of certain irritating chemicals, inadequate leaching conditions, or insufficient postprocessing may all result in gloves that cause irritation. In such cases, the problem may be solved by switching to an alternative manufacturer or merely to another lot of the same gloves.

Another source of irritation is glove powder. The donning agent absorbs the skin's natural moisture, leaving it extremely dry and vulnerable to injury by abrasive powder particles. Wearing a powder-free glove will eliminate this source of irritation.

When symptoms of irritation appear, wearing a larger glove, if work conditions permit, will increase air circulation and reduce friction during healing. Antiinflammatory agents are helpful, but should not be used during work hours because they are oil-based and may compromise the gloves' barrier integrity. Cotton and nylon glove liners have been helpful for a number of individuals prone to irritation. However, it must first be determined whether liners will contaminate assembly parts (e.g., fiber shedding on semiconductors) or create too much interference to properly perform tasks. In addition, because trapped soap and detergent are a major source of irritation, employees who must frequently wash hands should remove jewelry to permit adequate rinsing and drying. If at all possible, employees should change gloves frequently. This allows the skin to air and dry, if only briefly.

Various substances found in the work environment may penetrate through gloves, causing irritation. Solvents, alcohols, petroleum products, acids, and caustics will eventually permeate most gloves. Permeation rates depend on the chemical, temperature, and type of contact (intermittent splash or immersion), as well as the composition and thickness of the glove.

Allergic Contact Dermatitis. Allergic contact dermatitis is an allergic reaction to specific chemicals (known as contact sensitizers). Only individuals genetically programmed to respond to these chemicals will ever experience this type of reaction. Repeated exposure to specific chemical sensitizers increases the asymptomatic level of sensitization in genetically susceptible individuals until a critical threshold level is reached.³ Subsequent exposure will elicit a reaction.

Initial symptoms usually include redness and itching. Tiny clustered blisters may also appear, which elicit pain when scratched. After prolonged, repeated exposure to the chemical, a chronic condition may develop with dry thickened skin, cracking, peeling, sores, and papules. The appearance of allergic contact dermatitis may easily be confused with that of irritation. However, it differs in that the most intense level of symptoms appear from 6 to 48 hours after exposure (hence the term delayed-type hypersensitivity). In chronic cases, symptoms may eventually extend up the arm, beyond the glove cuff.⁴

Contact sensitizers are found in both synthetic and natural rubber latex gloves. The additives most frequently associated with reactions are the chemicals known as accelerators, which function as catalysts. Fortunately, there are only three basic categories of accelerators (thiurams, thiazoles, and carbamates), although they are used in varying amounts and combinations by different manufacturers. Approximately 15 to 25% of glove-related cases of allergic contact dermatitis are caused by chemicals other than accelerators. These potential contact sensitizers include antioxidants, colorants, preservatives, resins, and plasticizers.⁵

Isolation of the specific chemical responsible for an individual's allergic con-tact dermatitis may be determined by patch testing performed by a dermatologist. Alternatively, information supplied by the glove manufacturer may be sufficient to identify the causative agent. Once the responsible contact sensitizer has been identified, the employee can be provided with gloves containing a different accelerator mix or ones having lower overall chemical levels (hypoallergenic). Examples of this type of reaction include sensitivity to nickel, detergents, and poison oak.

Gloves labeled "hypoallergenic" were developed to address the needs of individuals who experience either irritant reactions or allergic contact dermatitis. These gloves are especially formulated and processed so as to minimize the level of residual chemicals in general and contact sensitizers specifically. For a company to use the "hypoallergenic" label, the gloves must undergo repeated challenges with a modified Draize test on 200 individuals under the supervision of a dermatologist.⁶ The results of the study, along with a description of the manufacturing processes used to obtain the hypoallergenic quality, must be submitted to FDA in a 510(k) notification.

Immediate-Type Hypersensitivity. Type I, or immediate-type, hypersensitivity is an allergy caused by sensitization to the proteins in latex from the rubber tree Hevea braziliensis. Repeated exposure to these allergens increases the asymptomatic level of sensitization in genetically susceptible individuals until a threshold level is reached. Subsequent exposure may result in any of several clinical symptoms, including itching, tingling, hives (which may spread over the entire body), swelling of the lips or eye-lids, runny nose, watery eyes, nasal congestion, tightening of the throat, abdominal cramping, headaches, and asthma, any or all of which may occur within seconds to an hour after exposure.⁷ Severe reactions, characterized by generalized swelling, a profound drop in blood pressure, and a sudden increase in heart rate may result in full anaphylactic shock. This condition can be life-threatening and requires immediate emergency medical attention. Examples of this type of allergy include sensitivity to bee stings, peanuts, and penicillin.

Test analysis has demonstrated that about 0.8% of the general public, 3 to 5% of hospital personnel in general, and 7 to 10% of surgical staffers show reactivity to the proteins in natural rubber latex, even if their levels of sensitization are not high enough for symptoms to occur. Individuals who generally suffer from allergies to avocados, kiwi fruits, bananas, and chestnuts are at greater risk of this form of latex allergy. Surgery early in infancy followed by multiple invasive procedures throughout childhood also increases the risk of Type I hypersensitivity. The prevalence of the condition in routinely gloved industrial personnel has yet to be established.

If the latex protein is kept low enough, even susceptible individuals may never reach a sensitization level high enough to elicit a reaction. Because the protein levels of gloves from different manufacturers vary by orders of magnitude, it is extremely important to compare levels when evaluating gloves. The method of analysis accepted by FDA is ASTM 5712-95. Individuals who must wear gloves routinely should be given low-protein gloves as early as possible in their careers to avoid becoming sensitized.

Sensitized individuals should also have emergency identification specifying their latex allergy and obtain a prescription for epinephrine from their allergist. All personnel must be trained to recognize and respond appropriately to potentially life-threatening anaphylactic shock. Inhalation of latex proteins bound to powder creates an additional risk to Type I­sensitized individuals. These employees must wear synthetic gloves and all coworkers must wear powder-free products.

Occupational Asthma. An increasing number of reported cases of occupational asthma have been associated with the use of powdered gloves.⁸ When gloves are snapped on and off and manipulated during tasks, coated powder particles are aerosolized and readily inhaled by employees.⁹ The same proteins and chemicals responsible for the dermal and systemic reactions already described can initiate equivalent reactions in the pulmonary tissues. Symptoms include a wide array of responses, such as an irritated throat and airways, coughing, sneezing, cold symptoms (rhinitis), headache and malaise (fatigue), asthma, and even anaphylaxis (shock).^10,11 The specific symptoms experienced depend on the substances transported, the individual's sensitivities, and any preexisting disease conditions.

Gloves labeled "powder-free" are extensively processed, eliminating many of the protein and chemical elements along with their particle vehicles. Thus, using powder-free gloves virtually eliminates cases of glove-related occupational asthma, except those that are initiated by a systemic reaction of immediate-type hypersensitivity due to other means of exposure.