A primer on protective gloves

Probably the single most common item of personal protection in any laboratory, even forensic ones, is the glove. Yet, it is also most likely to receive the least amount of thought or consideration and may be the most misunderstood. In the forensic laboratory, when we need to protect our hands, we often reach for whatever is closest, put it on, and think we are good to go. We are protected from…anything, everything. Whoever put that box of gloves on the shelf must have known the hazards faced and selected the proper type. Right? Why else would they be there?

Not so fast. Recall the highly publicized fatality of the New Hampshire researcher in 1997? She was working with dimethyl mercury. While transferring the material in a hood, a few small drops spilled onto the back of her latex gloved left hand. She cleaned up the spill, removed and disposed of her gloves, and didn’t give any more thought to the incident until being hospitalized five months later. Almost three hundred days post-exposure and after three months of aggressive treatment, she died from mercury poisoning.^1,2 Latex offers no protection for this organic substance and glove permeation occurred in about fifteen seconds.

Assess the Job and the Risks
Granted, this tragic accident is an extreme example and one not encountered in forensic labs, but thousands of accidents occur every year due to improper hand protection. Given the myriad glove types and materials, it is imperative that both employees and supervisors know which gloves are suitable for the task at hand (no pun intended). This brings us to the first step in a good hand protection program—conduct a detailed and thorough glove audit and job hazard analysis. We have written articles on this previously, but it boils down to simply identifying the hazard and the employees at risk, then selecting the right control measures, which include personal protective equipment, for the job. Things to keep in mind when performing the audit and hazard analysis are questions like:

• Can the procedure or process be changed to prevent or eliminate the hazard?
• Can a less hazardous material or substance be substituted?
• Will personal protective equipment solve the problem?
• Is the risk acceptable?

Identify the Hazard(s)
Hazards faced in a forensic laboratory span a wide array. Physical hazards such as cuts or punctures from broken glassware or burns from hot equipment or containers demand a much different protective glove than chemical hazards such as dermatitis, corrosive burns, or absorption. Fortunately, innovations in materials and technology have produced a huge selection of protective gloves for nearly any purpose. Advanced polymers and fibers provide superior protection from abrasion, punctures, and lacerations compared to the old standbys cotton and leather. These new materials provide even more protection when various coatings are applied.

When we enter the realm of the typical forensic laboratory though, the characteristic most needed is resistance to chemicals. Chemicals take all forms—liquids, dusts or powders, gases and vapors—and selecting the right glove will require a little homework. Lucky for us there are excellent manufacturer’s web sites available to help. (A few of these resources are given below.) But, before we leap into cyberspace we should know the terminology or lingo so we can decipher the mountain of information out there.Here are the most important ones:

• Contamination: occurs when the inside of the glove is contaminated either prior to or during donning (putting the glove on). Manufacturers cannot prevent this. Only careful and conscientious employees can. Make sure everyone is trained and follows good, safe housekeeping procedures.
• Penetration: happens when a substance passes through a seam or damaged glove, e.g. a pinhole or tear. Employees must be very attentive. Double-glove when handling extremely hazardous materials. Change to fresh gloves at the first sign of a problem or if in doubt about integrity.
• Degradation: happens when a chemical breaks down or damages the glove material. Manufacturers usually provide a rating over time. Selecting the best or most appropriate glove material, providing the highest rating for the longest time, is key to preventing exposures from degradation.
• Permeation: occurs when a substance passes through the intact glove material at the molecular level. This is commonly referred to as “breakthrough” and usually given in minutes. The larger the number the longer the glove material can be in contact with the chemical before breakthrough.