Permissable Exposure Levels

Safety Standards. Protection from laser beams involves not allowing laser radiation at a level higher than a maximum permissible exposure level to strike the human body. Maximum permissible exposure levels for both eyes and skin have been defined (55—57). One of the most common safety measures is the use of protective eyewear. Manufacturers of laser safety eyewear commonly specify the attenuation at various laser wavelengths. Under some conditions safety eyewear has been known to shatter or to be burned through (58), and it is not adequate to protect a wearer staring directly into the beam. 

Maleic Anhydride. The ACGIH threshold limit value in air for maleic anhydride is 0.25 ppm and the OSHA permissible exposure level (PEL) is also 0.25 ppm (181). Maleic anhydride is a corrosive irritant to eyes, skin, and mucous membranes. Pulmonary edema (collection of fluid in the lungs) can result from airborne exposure. Skin contact should be avoided by the use of mbber gloves. Dust respirators should be used when maleic anhydride dust is present. Maleic anhydride is combustible when exposed to heat or flame and can react vigorously on contact with oxidizers. The material reacts exothermically with water or steam. Violent decompositions of maleic anhydride can be catalyzed at high temperature by strong bases (sodium hydroxide, potassium hydroxide, calcium hydroxide, alkaU metals, and amines). Precaution should be taken during the manufacture and use of maleic anhydride to minimize the presence of basic materials. 

The ACGIH recommended maximum time-weighted average concentration in the workplace atmosphere for eight-hour daily exposure is 10 ppm. OSHA has set the permissible exposure level at 2 ppm. It maybe desirable to exclude alcohoHcs, persons with chronic disorders of the Hver, kidneys, and central nervous system, and those with nutritional deficiencies from working with chloroform. 

PEL means permissible exposure level (similar to TLV but devel-... 

Chronic Health Effect A chronic health effect is an adverse health effect resulting from long-term exposure to a substance. The effects could be a skin rash, bronchitis, cancer, or any other medical condition. An example would be liver cancer from inhaling low levels of benzene at your workplace over several years. The term is also applied to a persistent (months, years, or permanent) adverse health effect resulting from a short-term (acute) exposure. Chronic effects from long-term exposure to chemicals are fairly common. Recognize the PEL (permissible exposure level) for each substance in your workplace and minimize your exposure whenever possible. 

Typical units for LDjq values are milligrams or grams of material per kilogram of body weight (mg/kg or g/kg, recall that 1 kg = 2.2 pounds). Never be exposed to an LD50 dose of a hazardous chemical- by definition, there is a 50% chance this will kill you and if you survive you are not going to be in good shape. Pay close attention to the permissible exposure level (PEL) instead. This is a more realistic determination of the maximum safe exposure to a material and is usually based on the known effects of the chemical on humans, rather than laboratory animals. 

Releases of flammable vapors which, if discharged to the atmosphere, would in the event of inadvertent ignition result in radiant heat densities in excess of the permissible exposure level for personnel. This maximum level is defined as 19 Kw/m at ground level. 

Table 3 gives the threshold limit value (TLV) and permissible exposure level (PEL) of ammonia. 

Some sites are easy to elassify due to their inehision on the National Priorities List (NPL), state superfund, or other regulatory list. In other eases, debate ean and does arise to determine if a site should be treated as hazardous. Eor example, some sites eommonly referred to as brown fields have eontamination levels that are eonsidered low. Sometimes levels of eontamination are so low that exposure levels to workers do not reaeh aetion levels or permissible exposure levels (PEL). Some firms have ehosen to treat low-level eontaminated sites as if they fell under HAZWOPER requirements. This is a somewhat eonservative approaeh whieh provides a eomfort faetor for management and potentially responsible parties (PRP) or other entities. 

Toxicity of Alternatives to Chlorofluorocarbons HFC-134a and HCFC-123 (1996) Permissible Exposure Levels for Selected Military Fuel Vapors (1996)... 

OSHA ozone exposure limits, 17 815 OSHA Permissible Exposure Level (PEL), for sulfuric acid, 23 795 OSHA regulations, for vinyl chloride, 25 650, 651... 

Inspection of the table discloses that the permissible exposure level (PEL) = 10 ppm for methylamine. Since the... 

Permissible exposure level (PEL) Occupational Safety and Health Administration Official regulatory Allowable daily intake (ADI) Food and Drug Administration Official regulatory... 

First of all, the standard is oriented excessively to exacting specifications rather than performance. Nowhere is this more evident than in the requirements for the measurement of dust levels and exposures and instrumentation to accomplish these measurements. The methods of compliance with the permissable exposure levels offer employers little in the way of options. 

These two definitions reflect two sides of the same situation. In this book, the term critical effect(s) will be used for the hazard/effect considered as being the essential one(s) for the purpose of the risk characterization, e.g., for the establishment of a health-based guidance value, permissible exposure level, or Reference Dose. It should be noted that the critical effect could be a local as well as a systemic effect. It should also be recognized that the critical effect for the establishment of a tolerable exposure level is not necessarily the most severe effect of the chemical substance. For example, although a substance may cause a serious effect such as liver necrosis, the critical effect for the establishment of, e.g., an occupational exposure limit could be a less serious effect such as respiratory tract irritation, because the irritation occurs at a lower exposure level. 

The current permissible exposure levels for beryllium of 0.01 mcg/m3 averaged over a 30-day period or 2 mcg/m3 over an 8-hour period are insufficiently protective to prevent chronic beryllium disease. Both NIOSH and the ACGIH have recommended that the PEL and TLV be reduced to 0.05 mcg/m3. These recommendations have not yet been implemented. 

Acute- and chronic-duration inhalation exposure MRLs for diazinon were not derived because of a lack of suitable studies in the literature. Since diazinon is not volatile, inhalation exposure near toxic waste sites is probably less likely than oral or dermal exposure. However, the potential risk of adverse health effects from inhalation exposure to diazinon cannot be assessed without information on the levels actually present in the air around the site. The MRL level of 0.009 mg diazinon/m3 should be protective for individuals living near waste sites. NIOSH has recommended a Permissible Exposure Level (PEL) of 0.1 mg diazinon/m3 to protect the health of individuals who regularly use diazinon in their work the MRL level of... 

Maleic Anhydride. The ACGiH threshold limit value in air for maleic anhydride is 0.25 ppm and the OSHA permissible exposure level i PEL) is also 11.25 ppm. Maleic anhydride is a corrosive irritant to eyes. skin, and mucous membranes. Pulmonary edema (collection of fluid in Lite lungsl can result from airborne exposure. Maleic anhydride is combustible when exposed to heal or flame and can react vigorously on contact will oxidizers. 

Because radium is a radioactive substance, disposal of wastes containing radium is controlled by a number of federal and state regulations (see Chapter 7). Both the EPA and the Nuclear Regulatory Commission have promulgated regulations for land disposal of these wastes detailing containment requirements and permissible exposure levels based on radioactivity. 

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