6.C.2.5 Avoiding Injection of Hazardous Chemicals

Solutions of chemicals are often transferred in syringes, which for many uses are fitted with sharp needles. The risk of inadvertent injection is significant, and vigilance is required to avoid an injury. Use special care when handling solutions of chemicals in syringes with needles. When accompanied by a cap, syringe needles should be placed onto syringes with the cap in place and remain capped until use. Do not recap needles, especially when they have been in contact with chemicals. Remove the needle and discard it immediately after use in the appropriate sharps containers. Blunt-tip needles, including low-cost disposable types, are available from a number of commercial sources and should be used unless a sharp needle is Specifically required to puncture rubber septa or for subcutaneous injection.

6.C.2.6 Minimizing Skin Contact

6.C.2.6.1 Gloves

The OSHA Personal Protective Equipment (PPE) Standard (29 CFR §§ 1910.132-1910.138) requires completion of a hazards assessment for each work area, including an evaluation of the hazards involved and selection of appropriate hand protection. Wear gloves whenever handling hazardous chemicals, sharp-edged objects, very hot or very cold materials, toxic chemicals, and substances of unknown toxicity. No single glove material provides effective protection for all uses. Before starting, carefully evaluate the type of protection required in order to select the appropriate glove. The discussion presented here is geared toward gloves that protect against chemical exposure. (For information about gloves that protect against other types of hazards, see Chapter 7, section 7.F.1.4)

Select gloves carefully to ensure that they are impervious to the chemicals being used and are of correct thickness to allow reasonable dexterity while also ensuring adequate barrier protection. Choosing an improper glove can itself be a serious hazard in handling hazardous chemicals. If chemicals do penetrate glove material, they could be held in prolonged contact with the hand and cause more serious damage than in the absence of a proper glove. The degradation and permeation characteristics of the selected glove material must be appropriate for protection from the hazardous chemicals that are handled. Double gloves provide a multiple line of defense and are appropriate for many situations. Find a glove or combination of gloves that addresses all the hazards present. For example, operations involving a chemical hazard and sharp objects may require the combined use of a chemical-resistant (butyl, viton, or neoprene) glove and a cut-resistant (e.g., leather, Kevlar®) glove. Reusable gloves should be washed and inspected before and after each use. Be sure to wash your hands after wearing gloves and handling laboratory chemicals, to remove any skin contamination that might have occurred.

Gloves that might be contaminated with toxic materials should not be removed from the immediate area (usually a laboratory chemical hood) in which the chemicals are located. To prevent contamination of common surfaces that others might touch bare-handed, never wear gloves when handling common items such as doorknobs, handles, or switches on shared equipment, or outside the laboratory. Along the same lines, consider, before touching a surface while wearing gloves, whether it would be common for people to touch the surface with or without gloves and use appropriate precautions. For example, controls for hood nitrogen or water may be located outside the hood itself but may well be contaminated.

When working with chemicals in the laboratory, wear gloves of a material known to be resistant to permeation by the substances in use. Glove selection guides for a wide array of chemicals are available from most glove manufacturers and vendors. In general, nitrile gloves are suitable for incidental contact with chemicals. Both nitrile and latex gloves provide minimum protection from chlorinated solvents and should not be used with oxidizing or corrosive acids. Latex gloves protect against biological hazards but offer poor protection against acids, bases, and most organic solvents. In addition, latex is considered a sensitizer and triggers allergic reactions in some individuals. (For more information, see section 6.C. Neoprene and rubber gloves with increased thickness are suggested for use with most caustic and acidic materials. Barrier creams and lotions can provide some skin protection but are never a substitute for gloves, protective clothing, or other protective equipment. Use these creams only to supplement the protection offered by PPE.

According to the National Ag Safety Database (www.nasdonline.org), a program supported by NIOSH and the Centers for Disease Control and Prevention, materials that are used in the manufacture of gloves designed to provide chemical resistance include the following:

   Butyl is a synthetic rubber with good resistance to weathering and a wide variety of chemicals.

   Natural rubber latex is a highly flexible and conforming material made from a liquid tapped from rubber plants. It is a known allergen. (See section 6.C. for more information.)

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