. "Working with Chemicals." Prudent Practices in the Laboratory: Handling and Disposal of Chemicals. Washington, DC: The National Academies Press, 1995.
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Prudent Practices in the Laboratory: Handling and Disposal of Chemicals
with hazardous chemicals are given elsewhere in this volume (as discussed in Chapter 2). The reader is referred to Chapter 4, section 4.C, for detailed instructions on the transport of chemicals; Chapter 4, section 4.E on storage; Chapter 6 for information on use and maintenance of equipment and glassware; and Chapter 7 for information on disposal of chemicals.
5.CGENERAL PROCEDURES FOR WORKING WITH HAZARDOUS CHEMICALS
5.C.1Personal Behavior
Professional standards of personal behavior are required in any laboratory:
Avoid distracting or startling other workers.
Do not allow practical jokes and horseplay at any time.
Use laboratory equipment only for its designated purpose.
Do not allow visitors, including children and pets, in laboratories where hazardous substances are stored or are in use or hazardous activities are in progress.
If children are permitted in laboratories, for example, as part of an educational or classroom activity, ensure that they are under the direct supervision of qualified adults.
Make sure that teaching materials and publicity photographs show people wearing appropriate safety gear, in particular, eye protection.
5.C.2Minimizing Exposure to Chemicals
Precautions should be taken to avoid exposure by the principal routes, that is, contact with skin and eyes, inhalation, and ingestion, which are discussed in detail in Chapter 3, section 3.C.
5.C.2.1 Avoiding Eye Injury
Eye protection should be required for all personnel and visitors in all locations where chemicals are stored or used. Eye protection is required whether or not one is actually performing a chemical operation. Visitor safety glasses should be made available at the entrances to all laboratories.
Researchers should assess the risks associated with an experiment and use the appropriate level of eye protection:
Safety glasses with side shields provide the minimum protection acceptable for regular use. Safety glasses must meet the American National Standards Institute (ANSI) standard Z87.1-1989, Standard for Occupational and Educational Eye and Face Protection, which specifies a minimum lens thickness, certain impact resistance requirements, and so on.
Safety splash goggles or face shields should be worn when carrying out operations in which there is any danger from splashing chemicals or flying particles. These thin shields do not provide protection from projectiles, however.
Goggles are preferred over regular safety glasses to protect against hazards such as projectiles, as well as when working with glassware under reduced or elevated pressures (e.g., sealed tube reactions), when handling potentially explosive compounds (particularly during distillations), and when employing glassware in high-temperature operations.
Because goggles offer little protection to the face and neck, full-face shields should be worn when conducting particularly hazardous laboratory operations. In addition, glassblowing and the use of laser or ultraviolet light sources require special glasses or goggles.
Ordinary prescription glasses do not provide adequate protection against injury. Prescription safety glasses and goggles can be obtained.
Contact lenses offer no protection against eye injury and cannot be substituted for safety glasses and goggles. It is best not to wear contact lenses when carrying out operations where chemical vapors are present or a chemical splash to the eyes or chemical dust is possible because contact lenses can increase the degree of harm and can interfere with first aid and eye-flushing procedures. If an individual must wear contact lenses for medical reasons, then safety glasses with side shields or tight-fitting safety goggles must be worn over the contact lenses.
5.C.2.2 Avoiding Ingestion of Hazardous Chemicals
Eating, drinking, smoking, gum chewing, applying cosmetics, and taking medicine in laboratories where hazardous chemicals are used should be strictly prohibited. Food, beverages, cups, and other drinking and eating utensils should not be stored in areas where hazardous chemicals are handled or stored. Glassware used for laboratory operations should never be used to prepare or consume food or beverages. Laboratory refrigerators, ice chests, cold rooms, ovens, and so forth should not be used for food storage or preparation. Laboratory water sources and deionized laboratory water should not be used for drinking water.
Laboratory chemicals should never be tasted. A pipet bulb or aspirator should be used to pipet chemi-