when and where a reasonable chance exists of your hands contacting chemicals or biologicals that have harmful or unknown properties. At home you're "allowed" to get acetone or ethyl acetate (nail polish removers), or the neighbor kid's blood, or Bo-Peep ammonia, or gasoline, or motor oil, etc.... all over your hands (none of these recommended of course!). But not at work. Gloves should NOT be worn in public corridors, nor when touching doorknobs, light switches, telephones, radio dials.... or any shared-use item which will be used by others who are not wearing gloves. If your work area has a clear and completely enforced rule that all workers must wear gloves when touching these latter items (excepting the corridor wearing), that rule would supersede the previous statement.
It is necessary that the gloves you choose prevent potentially harmful chemical and biological materials from contacting your skin. They must be chosen very carefully for work with extremely toxic chemicals and dangerous pathogens. Chemical resistance properties -- degradation and permeation test results -- are tested using standard ASTM methods for many (non-disposable) gloves, and published resistance guides exist for chemical-protective materials in general. Consult such a guide when choosing gloves, and do NOT EVER use disposable gloves where known protection is needed or desired. (Because they only provide an unknown level of protection.) ORCBS glove guide
don (put on) gloves and check for flaws, weak spots, breaches. An extremely tight fit is undesirable because it stretches and weakens, and it impedes rapid removal. Remove (doff) gloves before leaving your work area, and before touching items that will be touched by others who are not wearing protection. Before removing (unless very rapid removal is urgent), clean any gross chemical contamination from gloves, by wiping or rinsing. For trivial and/or nontoxic contamination, or when removal of contamination is not possible, gloves are to be removed in such a manner that the external surface of either glove does not touch your unprotected skin; use your gloved dominant hand to remove the other glove, then use that unprotected non-dominant hand to take hold of an uncontaminated part of the remaining glove (usually under glove cuff or opening at wrist) and pull or push the dominant-hand glove over the fingers.
Not all gloves resist all chemicals, and NO gloves resist ANY chemicals indefinitely. Some types of disposable gloves are being found to be less effective at stopping viruses (latex and non-latex rubber are currently deemed best for pathogens). Disposable gloves offer extremely marginal protection from chemicals in most cases and should be removed immediately on contamination. Select gloves carefully using data generated by standard tests.
Disposable gloves should never be re-used (put on again after removing). All gloves must be inspected before every use, for possible holes, tears, weak areas. Reusable gloves should be cleaned after each use, and stored so that they may dry inside and out. If your hands sweat, it is prudent to wear a light disposable under reusable gloves to prevent their inside from becoming damp. Any gloves from which hazardous chemical contamination cannot be removed must be collected in a hazardous waste and disposed of through REM. Gloves contaminated with biologicals should be handled as biohaz or look-alike waste, depending on the contamination. The useful life of reusable gloves will vary drastically depending on the frequency of use, duration of exposure to chemicals, the identity of chemicals to which they are exposed, and the conditions of cleaning and storage.