Hazards in the Laboratory

Various types of hazards are encountered in the operation of a clinical laboratory. These hazards must be identified and labeled, and work practices developed for dealing with them. The major categories of hazards encountered include biological, chemical, electrical, and fire hazards. 

Clinical laboratories deal with each of the nine classes of hazardous materials. These are classified by the United Nations (UN) as (1) explosives, (2) compressed gases, (3) flammable liquids, (4) flammable solids, (5) oxidizer materials, (6) toxic materials, (7) radioactive materials, (8) corrosive materials, and (9) miscellaneous materials not elsewhere classified. Shipping and handling of Class (6) toxic materials, 

The upper half of the label for corrosive materials shows a metallic bar and a hand, both of which are being eaten away by drops of fluid the black bottom half of the label is lettered corrosive in white. The bottom corner shows the digit 8.  

The system is used by the DOT for shipping hazardous materials however, when the hazardous material reaches its destination and is removed from the shippmg container, this identification is lost. The laboratory must then label each individual container. Usually the information necessary to classify the contents of the container appropriately is contained on the shipping label and should be noted. Important first-aid information is also usually provided on this label. 

Descriptive labels, such as corrosive, flammable, poison, and explosives may also be used. Obviously, some containers may require two or three labels because several types of hazard are involved. 

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Trichloromethyl chloroformate is useful in synthesis as a substitute for phosgene, which, owing to its high volatility and toxicity, presents a severe hazard in the laboratory. Although trichloromethyl chloroformate is toxic, it is a dense and less volatile liquid, b.p. 128°, d l 1.65, having a vapor pressure of only 10 mm. at 20°. Consequently it is more easily handled in a safe manner than phosgene. 

Most mechanical hazards in the laboratory can be avoided by good planning. There must be no obstructions in traffic areas, particularly those needed for rapid evacuation in case of emergency. Wide hallways may look like good parking places for movable equipment not currently in use. They may also seem convenient for storage of reagents and supplies that temporarily... 

Safety Precautions Safety symbols and statements warn you of potential hazards in the laboratory. Before beginning any activity, refer to page xiv to see what these symbols mean. 

Why is PH3 a particular hazard in the laboratory and in industrial chemical synthesis Is it very toxic What are its major toxic effects ... 

Chemicals that present a particular hazard in the laboratory as a result of their physical and reactive properties include the following categories, identified for the pmposes of risk assessment and for product labelling in UK and European Union (EU) health and safety regulations ... 

Diethyl ether is extremely flammable. Its volatility and low ignition temperature make it one of the most dangerous fire hazards in the laboratory. Ether vapor forms explosive mixtures with air due to the formation of unstable peroxides. Diethyl ether may react violently with halogens or strong oxidizing agents. 

A placard or other warning device shall be placed on the door or on the wall immediately adjacent to the door identifying the major classes of hazards in the laboratory (See Chapter 2, Figures 2.6 and 2.7). 

Favero, M.S., Biological hazards in the laboratory, in Proceedings of Institute on Critical Issues in Health Laboratory Practice, Richardson, J.W., Sdioenfeld, E., Tullis, J.W., and Wagna, W.W., Eds., The DuPont Company, Wilmington, DE, 1986, 1. 

Flammable substances, those that readily catch fire and bum in air, may be sohd, hquid, or gaseous. The most common fire hazard in the laboratory is a flammable liquid or the vapor produced from such a liquid. An additional hazard is that a compound can enfiame so rapidly that it produces an explosion. Propo" use of substances that can cause fires requires knowledge of their tendencies to vaporize, ignite, or bum undo" the variety of conditions of use in the laboratory. 

Imagine for a moment that a chemist wants to use a reaction that is highly exothermic, or is energetic in some fashion (say rapid CO2 evolution), or maybe it is exothermic with a rapid evolution of hydrogen (explosion hazard). In the laboratory, as most chemists are trained, this can be handled in one of several ways. The chemist might precisely control the order and/or rate of addition of a particular reagent or... 

An Array of Rays—Ionizing Radiation Hazards in the Laboratory Presents an... 

Corrosive chemicals are common hazards in the laboratory and also in our homes in the form of cleaning agents. Corrosives are defined as chemicals that cause harm or injury by damaging and destroying tissue, such as eyes or skin, at the point of contact or the exposure site (see Figure 5.1.1.1). Table 5.1.1.1 lists some corrosives that may be encountered in the first year of chemistry laboratory experiments. Corrosives can be gases, liquids, solids, or solutions. 

AN ARRAY OF RAYS—IONIZING RADIATION HAZARDS IN THE LABORATORY... 

Electrical issues represent one of the most frequently encountered hazards in the laboratory. Although multioutlet plugs are common to most worksites, it is recommended that these not be used unless a built-in circuit breaker is installed. The total amperage on any given circuit should not exceed the rating printed on the outlet box (commonly, 15 amps). The area immediately surrounding circuit breaker boxes must be kept clear as a work area for maintenance personnel. In most cases, display placards on the doors can be used to indicate the need for cleared space around circuit boxes. 

The National Fire Protection Association (NFPA) develops and issues fire codes that are used by fire marshals and the authority having jurisdiction to enforce required fire safety measures. NFPA issued the new NFPA 45-2015 Standardfor Fire Protection for Laboratories Using Chemicals which included Chapter 12 on Educational and Instructional Laboratory Operations. This new section established new requirements for teachers and instructors who perform demonstrations. Instructors performing demonstrations must perform a documented risk assessment, provide a safety briefing to students, provide adequate personal protective equipment (PPE), and use secured safety barriers between the student and the demonstration to prevent personal injury unless there is at least 10 feet between the demonstration and the students. Institutions are required to train instmctors in fire safety procedures, emergency plans, hazards in the laboratories, use of PPE, and how to conduct risk assessments. 

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