Hazards, chemical electrical

Ethan and Little, in their article on risk discuss the confusion between the concepts of hazard and risk, where there is tendency to use the terms interchangeably. As they noted a hazard is a potential source of harm . However, Risk is the chance that the adverse effects of unidentified hazards will occur (Ethan Little, 2011). The source of the hazard (chemical, electrical, radiation, etc.) establishes the physical condition that creates the potential for injury or damage. However, the risk is a combination of the potential severity of the incident that might occur and its probability of occurrence or on the frequency of exposure to the hazard. 

Accidents have occurred because hot water was not treated with respect. Five men were killed when a plastic hot-water tank split along a seam [14J. On another plant, a man, about to make some tea, caught his sleeve on the tap of an electric water heater. The heater fell over, 2 gal of hot water fell on him, and he died in the hospital five days later [15]. The heater should have been fixed to the wall. If it had contained a hazardous chemical, it would have been secured, but no one thought hot water was hazardous. Chemicals are not the only hazards on a plant. 

In the sector of electrical and electronic equipment, the RoHS Directive, as explained, has successfully resulted in reduction of hazardous chemicals in line with goals of the RISKCYCLE project and has reduced many problems. This raises... 

Checklists should be applied only during the preliminary stages of hazard identification and should not be used as a replacement for a more complete hazard identification procedure. Checklists are most effective in identifying hazards arising from process design, plant layout, storage of chemicals, electrical systems, and so forth. 

Prudent Practices for Handling Hazardous Chemicals in Laboratories, National Academy Press, Washington, D.C., I98. General laboratory practice for hazardous materials, electrical hazards, laboratory ventilation, storage of chemicals, disposal of chemicals, and threshold limit values for chemical substances. 

Electric arc furnace dust is a listed hazardous chemical waste. This material is deemed hazardous because it contains relatively high concentrations of heavy metals. The waste consists of the emission control dust or sludge collected from electric arc furnaces during the manufacture of iron and steel. The principle chemicals of concern and their concentrations are listed in Table 7.5 (EPA, 1988). 

Table 7.5—Concentrations of hazardous chemicals in untreated, high-zinc electric arc furnace dust waste.

As indicated in Table 7.6, all hazardous chemicals in electric arc furnace dust are assumed to induce deterministic responses. The possible responses include renal toxicity, effects on the cardiovascular system, dermal or ocular effects, decrease in body weight, hepatic toxicity, and respiratory toxicity. Decrease in body weight is not a response in a particular organ but is assumed to be a health effect of concern. All deterministic responses are assumed to be induced by more than one chemical in the waste. Furthermore, some of the chemicals (barium, beryllium, chromium, and lead) are assumed to induce all responses. 

The example analyses for electric arc furnace dust in Section 7.1.7 and a hazardous chemical waste in Section 7.1.8 lead to an important conclusion about these particular wastes. The concentrations of heavy metals, especially lead, in the electric arc furnace waste clearly are sufficiently high that long-term exposure to the waste by an inadvertent intruder may need to be precluded in order to ensure that deterministic effects would not occur. In addition, for either waste, the stochastic risk that could result from unrestricted release of a disposal site might exceed acceptable levels, due to the concentrations of heavy metals that induce stochastic effects. Both of these factors indicate that these wastes may be classifiable as low-hazard only if perpetual control would be maintained over near-surface disposal sites to prevent long-term exposures of inadvertent intruders. Such a conclusion also was obtained in the example of uranium mill tailings discussed in Section 7.1.5. 

Gas cylinders must be chained securely to the wall or laboratory bench (see pp. 644-646 and Appendix C). There is some hazard of electrical shock or short circuit from exposed terminals. Check all electrical connections carefully before plugging into the 110-V ac line. Note also that CCI4 is used in a minor way as a solvent in the preparatory work. This is a potentially hazardous chemical (see p. 197, CCI4 hazards) and should be handled with care. 

It is again strongly recommended that distillation of methyl or ethyl azodicarboxylate be carried out from a thermally controlled bath, not an electrically heated mantle, for the latter may overheat the material being distilled. The bath should have a thermometer in it to keep track of the bath temperature, which should not be allowed to go higher than 130°C. The bath should be lowered at the end of the distillation. The distillation should be shielded on all sides by fixed shielding, as described in "Prudent Practices for Handling Hazardous Chemicals in Laboratories", National Academy Press, Washington, DC (1981), pp. 170-171 see also Org. Synth., Coll. Vol. VIin 993, p. vi. 

The major use of vinyl chloride (also known as vinyl chloride monomer, VCM) is in the production of the ubiquitous plastic, PVC or polyvinylchloride, which began to be used in the 1940s. This polymer is used in a wide variety of products ranging from cling film, bottles, car components, pipes, electrical insulation, and window frames. Unfortunately, vinyl chloride, which is used to make the plastic, is a hazardous chemical. For this reason and because PVC is an organochlorine compound, it has received a bad press. It has important properties, however, such as flexibility, toughness, and durability, that make it an extremely useful and versatile material. 

The hazardous processes are isolated so they do not constitute danger to other personnel and their activities fuel, chemicals, electric power generators, and boilers should be isolated from other facihties to avoid danger. 

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. 

International Organization for Standardization and the International Electrotechnical Commission. Over 1000 companies are members of the ANSI. One of its primary concerns is safety in such fields as hazardous chemicals, protective clothing, welding, fire control, electricity and construction operations, blasting, etc. Its address is 1819 L Street, NW, Washington, DC 20036. Website http //... 

The flame retardants, polybrominated diphenyl ethers or PBDEs, exemplify both the benefits and downsides of the modern chemical economy. Every year manufacturers of TVs, computers, furniture, electrical wires, draperies, and other products add chemical flame retardants to their products to protect the public from the dangers of fire. But in adding PBDE flame retardants to their products they have created, however unintended, another public hazard—exposing humans and animals across the globe to hazardous chemicals. 

Review of surrounding plants/facilities Existing pipe racks Maintenance and operations access Sewers and storm water drainage Existing fire and radiation circles Hazardous chemical releases from upwind locations Existing electrical area classification Close access to substations... 

This section can only touch upon the broad topic of safe laboratory working procedures because of the immense scope of the subject. The procedure to be followed here is to provide generic approaches to most of the hazards covered rather than discuss specific instances in which a given hazard could occur. Some of the more common areas which offer the potential for mishaps will be covered in some detail, but undoubtedly there will be areas that are considered comparably important by many that will be touched upon lightly or not at all. Sections will be devoted to a small number of the more hazardous chemicals to illustrate the precautions that need to be taken when working with such materials. In addition to physical hazards, such as fire, electrical hazards, and explosions, health risks will be discussed in some detail, since in many... 

RoHS directive stands for Restriction of the use of certain Hazardous Substances in Electrical and Electronic Equipment. The purpose of the directive is to control the use of certain hazardous chemical substances such as mercury, cadmium, lead, hexavalent chromium, polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE) for electrical and electronic equipment. In the EU, no one is allowed to place electric and electronic equipment on the market that would include those hazardous substances exceeding a certain limit. The regulation values are mentioned in Table 2. 

Street shoes may not be appropriate in the laboratory, where both chemical and mechanical hazards may exist. Substantial shoes should be worn in areas where hazardous chemicals are in use or mechanical work is being done. Clogs, perforated shoes, sandals, and cloth shoes do not provide protection against spilled chemicals. In many cases, safety shoes are advisable. Shoe covers may be required for work with especially hazardous materials. Shoes with conductive soles are useful to prevent buildup of static charge, and insulated soles can protect against electrical shock. 

A hazard is something with the potential to cause harm, for example, chemicals, electricity or working above ground. 

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