Exposures in the Workplace

The inherent hazards associated with chemical exposures in a warehouse are often ignored or treated casually. There are chemicals of one kind or another in every warehouse. A particular chemical could be very dangerous or be a minor hazard. Every employee must know the risks of each chemical being stored or handled within or outside the building. Management and employees should be knowledgeable in specific warehouse hazards. This chapter will focus on the following details associated with chemicals in the warehouse  

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EH56 Biological monitoring for chemical exposures in the workplace. 

Acute exposure to trichloroethylene and its decomposition products (e.g., dichloroacetylene) has also led to residual neuropathy, characterized by nerve damage. This neuropathy is characterized by facial numbness, jaw weakness, and facial discomfort (indicating damage to cranial nerves V and VII) which can persist for several months (Buxton and Hayward 1967 Feldman 1970). Chronic exposure in the workplace has also been associated with damage to the cranial nerves in several cases (Bardodej and Vyskocil 1956 Barret et al. 1987 Cavanagh and Buxton 1989). Persons who have died from overexposure have shown degeneration of cranial nuclei in the brain stem (Buxton and Hayward 1967). Some of these effects may be attributed to... 

Production, Import/Export, Use, and Release and Disposal. Lead is produced and imported for widespread use in the United States. Therefore, the potential for human exposure in the workplace, the home, the environment, and at waste sites may be substantial. 

Dermal exposure to chemicals is one of the leading causes of job-related illness as reported by the National Institutes for Occupational Safety and Health. As jet fuel is the primary occupational exposure of military and aviation industry personnel, there is elevated concern regarding JP-8 dermal exposures in the workplace. Several anecdotal reports confirm that persons exposed to jet fuel experience itching or burning skin, skin redness or rash, skin dryness or dermatitis, skin lesions or weeping, or skin sensitization [32,33,34], yet little is known regarding possible systemic effects following dermal exposure. 

The quality of life experienced by people with MCS is shaped, to a great extent, by the level of awareness of environmental health issues where they live and work. Some are recipients of workplace accommodations in accordance with the Americans with Disabilities Act others are harassed and ostracized at work, or fired from their jobs. Some disabled by chemical exposures in the workplace receive workers compensation the majority of chemical-illness claims are denied. Some cities, schools and other institutions have adopted fragrance-free policies and Integrated Pest Management (IPM) programs to reduce chemical barriers and dangers in public places others still resist despite all the prevalence studies and research indicating that MCS is a serious threat to public health. 

At the workplace, exposure to phenol can occur from breathing contaminated air. However, skin contact with phenol during its manufacture and use is considered the major route of exposure in the workplace. It has been estimated that about 584,000 people in the United States are exposed... 

In work-aggravated asthma, a worker with preexisting asthma has worsening of asthma symptoms due to exposures in the workplace. These exposures may be irritant chemicals, cold air, or allergens to which the worker was sensitized prior to hire. The diagnosis is made if the asthma was not active within 2 years before the hire date and there is (1) worsening of asthma symptoms on workdays and (2) serial spirometry tests and /or repeat PEER measurements suggesting a work-related pattern. 

From a health perspective, there are few redeeming features of solvents except when used as anesthetics. Clearly the simple recommendation is to avoid exposure unless administered for some medical reason. In the workplace, appropriate ventilation and personal safety equipment should be in place at all times. There are numerous national and international regulations on solvent exposure in the workplace. Substitution of less-toxic solvents in processes and products can reduce the risk of injury. 

As shown in Figure 2-4, there is a considerable body of data on the health effects of carbon tetrachloride in humans, especially following acute oral or inhalation exposures. Although many of the available reports lack quantitative information on exposure levels, the data are sufficient to derive approximate values for safe exposure levels. There is limited information on the effects of intermediate or chronic inhalation exposure in the workplace, but there are essentially no data on longer-term oral exposure of humans to carbon tetrachloride, most toxicity studies have focuses on the main systemic effects of obvious clinical significance (hepatotoxicity, renal toxicity, central nervous system depression). There are data on the effects of carbon tetrachloride on the immune system, but there are no reports that establish whether or not developmental, reproductive, genotoxic, or carcinogenic effects occur in humans exposed to carbon tetrachloride. 

TLV refers to concentrations of substances in parts per million or milligrams per cnbic meter in the air to which most workers can be exposed on a daily basis without harm. These values apply to the workplace only. They are not intended as guidelines for ambient air quality standards for the population at large. TLVs should be treated as guidelines only and not as fixed standards. The recommended goal is to minimize chemical exposure in the workplace as much as possible. 

Occupational and environmental poisoning with metals, metalloids, and metal compounds is a major health problem. Exposure in the workplace is found in many industries, and exposure in the home and elsewhere in the nonoccupational environment is widespread. The classic metal poisons (arsenic, lead, and mercury) continue to be widely used. (Treatment of their toxicities is discussed in Chapter 57.) Occupational exposure and poisoning due to beryllium, cadmium, manganese, and uranium are relatively new occupational problems, which present new and previously unaddressed problems. 

Overall, our analyses have shown that HERP values for some historically high exposures in the workplace—to butadiene and tetrachloroethylene—and to some pharmaceuticals—clolibrate —rank high, and that there is an enormous background of naturally occurring rodent carcinogens in typical portions of common foods. The background of natural exposures casts doubt on the relative importance of low-dose exposures to residues of synthetic chemicals such as pesticides. (A committee of the National Research Council of the National Academy of Sciences reached similar conclusions about natural vs. synthetic chemicals in the diet, and called for further research on natural chemicals.) 16... 

In Febmary 1990 the Occupational Safety and Health Administration lU.S.) published a report llrat summarizes the history of cadmium regulation, studies of health problems, and risk calculations for cancer, kidney damage, and other disorders. This report represents a formal step toward implementation of stricter limits on cadmium exposure in the workplace. Some authorities admit that considerably more research is required. 

TLY Threshold Limit Value guidelines suggested by the American Conference of Governmental Industrial Hygienists to assist industrial hygienists with limiting hazards of chemical exposures in the workplace. 

World Health Organization, Biological Monitoring of Chemical Exposure in the Workplace, World Health Organization, Geneva, Switzerland, 1996. 

The chemical profession and the federal government have attempted to minimize worker exposure to compounds or reactions that result in an acute or chronic biological response. The American Chemical Society has sponsored several symposia during the past few years in which chemists have discussed potentially hazardous compounds. However, to assess the extent of hazardous exposure in the workplace, new demands have been made on analytical chemistry. The analytical chemist has responded by producing and developing new methodologies and instrumentation that permit the detection and monitoring of extremely low level concentrations of hazardous substances. 

Workplace exposure to chemical substances and the potential for pulmonary toxicity are subject to regulation by the Occupational Safety and Health Administration under the Occupational Safety and Health Act (OSHA), including the requirement that potential hazards be disclosed on material safety data sheets (MSDS). (An interesting question arises as to whether carbon nanotubes, chemically carbon but with different properties because of their small size and structure, are indeed to be considered the same as or different from carbon black for MSDS pur-oses.) Both government and private agencies can be expected to evelop the requisite threshold limit values (TLVs) for workplace exposure. Also, EPA may once again utilize TSCA to assert its own jurisdiction, appropriate or not, to minimize exposure in the workplace. 

For occupational exposures, Permissible Exposure Levels (PELs), Threshold Limit, Values (TLVs), and NIOSH Recommended Exposure Levels (RELs) are developed. They represent dose levels that will not produce adverse health effects from repeated daily exposures in the workplace. The method used to derive them is conceptually the same. Safety factors are used to derive the PELs, TLVs, and RELs. 

I have chosen to deal with vinyl chloride in my discussion of exposure in the workplace as it serves to demonstrate the problems that may arise from exposure to novel chemicals, how these can be prevented, and how crucial a knowledge of toxicology is to occupational health and the safe use of chemicals. 

Asbestos fibers have also been measured in urine (see Section 7.1), and limited data indicate that above average exposures in the workplace (Finn and Hallenbeck 1984) and through drinking water (Cook and Olson 1979) can be detected by this means. However, only a tiny fraction of inhaled or ingested fibers is... 

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