Exposure, occupational levels

Idaho Acceptable concentration Occupational exposure level 0.005 mg/m 0.1 mg/m Idaho Department of Health and Welfare 1999... 

Reproductive Effects. There is sufficient qualitative evidence to support the conclusion that at high occupational exposure levels lead has significant adverse effects on human reproduction, including increased incidences of spontaneous abortion, miscarriages, and stillbirths. The mechanisms responsible for these effects are unknown at this time, but many factors may contribute to these results. These factors include indirect effects of lead on maternal nutrition or hormonal status before and during pregnancy to... 

Data concerning occupational exposure levels of heptachlor are very limited. An industrial hygiene survey conducted in 1977 at the Velsicol Chemical Corporation, Memphis, Tennessee, a plant that manufactured heptachlor, detected heptachlor in workplace air at levels ranging from 0.025 to 0.202 mg/m (1.64-13.2 ppb) (Netzel 1981). Data from the National Occupational Exposure Survey (NOES) conducted by NIOSH from 1981 to 1983 were not available for heptachlor or heptachlor epoxide. 

Dichlorobenzidine does not naturally oceur in the environment (lARC 1982a). 3,3 -Diehlorobenzidine was not detected in ambient air of two dyestuff produetion plants at detection limits of 5 (Narang et al. 1982) and 0.1 ng/m (Riggin et al. 1983). More reeent data on occupational exposure levels indieate the presence of levels 0.6-2.5 g/m in 3,3 -diehlorobenzidine production and pigment manufaeturing plants in Germany (DCMA 1989). 

Concentrations of cyclohexanol in urine and cyclohexane in whole blood and serum have shown significant correlations with occupational exposure levels. ... 

Reproductive effects from lead exposure have been documented in animals and human beings of both sexes. High occupational exposure levels in pregnant women have been associated with increased incidences of spontaneous abortions, miscarriages, and stillbirths. Some studies also seem to indicate that prenatal exposure to lower levels of lead may increase the risk of preterm delivery and reduced birth weight. Lead penetrates the placental barrier and has caused congenital abnormalities in animals. There is no conclusive evidence, however, that low-level lead exposure leads to an increased incidence of... 

Few data, especially recent data, are available on occupational exposure levels of pyridine. In 1978, the United States P Tidine Task Force of the Interagency Testing Committee reported that in United States workplaces where pyridine was manufactm-ed or used as a chemical intermediate or as a solvent, workers were exposed to 8-h time-weighted average (TWA) pyridine concentrations ranging from 0.008 to 1.0 ppm [0.026 to 3.24 mg/m ]. Technicians working in quality control and research and development laboratories of one of the pyridine manufacturers were exposed to TWA concentrations (measiu ed over 6-h periods) of no more than 0.09 ppm [0.29 mg/m ] (Santodonato etal, 1985). 

Study Group on Comparative Risk Ad Hoc Group on Video Display Iferminals Ibsk Force on Occupational Exposure Levels... 

NIOSH recommends that the occupational exposure level not exceed 100 pg/m3 for a 10-hour TWA workday (NIOSH 1992). In addition, the American Conference of Governmental Industrial Hygienists has recommended a time-weighted average threshold limit value (TWA-TLV) of 100 pg/m3 for occupational exposure to diazinon (ACGIH 1986). 

This is the only available well conducted intermediate-duration inhalation study for diazinon. In an acute-duration study in which rats were exposed to 2,300 mg/m3 diazinon for four hours (Holbert 1989), mild signs of organophosphate toxicity were noted (nasal discharge, salivation). NIOSH recommends an occupational exposure level of 0.1 mg/m3, approximately 100-fold higher than the MRL. 

According to the 1981-83 National Occupational Exposure Survey (NOES, 1997), approximately 40 000 workers in the United States were potentially exposed to toluene diisocyanates (see General Remarks). Occupational exposures to toluene diisocyanates may occur during their production and in the production of polyurethane foams, elastomers, coatings, adhesives and finishes. Exposure may also occur in the use of some polyurethane products. Data on occupational exposure levels have been presented in a previous monograph (lARC, 1986). More recent exposure levels have been reported in connection with epidemiological (Section 2) and toxicological (Section 4) studies. 

Bis(2,3-epoxycyclopentyl)ether is a synthetic organic liquid which has been used as a component and modifier of epoxy resins. Measurements of occupational exposure levels have not been reported (IARC, 1989). 

Cyclohexanone is a synthetic organic liquid used primarily as an intermediate in the production of nylon. Other minor applications are as an intermediate, additive and solvent in a variety of products. Occupational exposure levels have been measured in some industries (lARC, 1989). 

Dimethyl hydrogen phosphite is used as a flame retardant on nylon 6 fibres, as a chemical intermediate in the production of pesticides and in lubricant additives and adhesives. No data on occupational exposure levels were available. A potential source of exposure to this chemical is from its occurrence as a degradation product of the chemical intermediate trimethyl phosphite and of pesticides such as trichlorphon and malathion (lARC, 1990). 

Tetrakis(hydroxymethyl)phosphonium salts are used to produce crease-resistant and flame-retardant finishes on textile fabrics, including children s nightwear. No data on occupational exposure levels were available (lARC, 1990). 

Tris(2-chloroethyl) phosphate is used as a flame retardant in plastics, especially in flexible foams used in automobiles and furniture, and in rigid foams used for building insulation. No data on occupational exposure levels were available. Tris(2-chloroethyl) phosphate has been detected in drinking-water, river water, sea water and sediments in various parts of the world (IARC, 1990). 

The guinea pig intratracheal test has been used to establish the relative potency of different detergent enzymes and establish safe occupational exposure levels. As the name implies, guinea pigs are sensitized by intratracheal exposure and induction of cytophilic antibodies are assessed. Dose responses obtained for new enzymes are compared to a reference enzyme for which safe exposure levels have been established. The relative potency of the new enzyme to this reference is used to establish a safe exposure level for the new enzyme. 

IRIS = Integrated Risk Information System MCL = maximum contaminant level MCLG = maximum contaminant level goal NIOSH = National Institute for Occupational Safety and Health OEL = occupational exposure level OSHA = Occupational Safety and Health Administration PEL = permissible exposure limit PQL = practical quantitation limits RCRA= Resource Conservation and Recovery Act REL = recommended exposure limit ... 

Biological monitoring has been used to relate serum and urine chromium levels to occupational exposure levels. A statistically significant (r=0.95, p<0.001) relationship between total chromium exposure and urinary chromium concentrations at the end of the workday were observed in five welders exposed to chromium(VI) compounds. The urinary chromium concentrations of 40-50 pg/L immediately after work... 

In this approach it is proposed that mechanistic data be used to support the assessment of cancer risk at low (environmental or occupational) exposure levels, in the absence of human or laboratory animal tumor data in this exposure range. This represents a significant advance over previous practice whereby, for mutagenic chemicals, a default approach was used that required a linear extrapolation from... 

Fig. 8.1 Dose-response curve showing log dose on the X-axis and percent response (Effect) on the Y-axis. The figure illustrates the location of regulatory values such as the NOEL, Occupational Exposure Levels (OELs) or environmental standards such as Acceptable Daily Intake (ADI)...

Samples may be collected over 24-h periods or for shorter periods of exposure time, depending upon the design of the study and the sensitivity of the method. When the usual gas or liquid chromatographic analysis procedures are used, air volumes of O.OI to I m are sufficient for occupational exposure levels (i.e. air concentrations of O.I to lOmg/m ) and 1 to 10m for non-occupational exposures (i.e. 0.01 to 10 p,g/m ). 

The so-called Occupational Exposure Level (OEL) is a key parameter for people responsible for the safety issues in pharmaceutical and chemical industries. " The assessment and the application of the OEL are particularly important also for hazardous pharmaceuticals that are routinely handled within the pharmaceutical companies. There are different approaches to determine the OEL of a certain chemical and its relation to the handling/use of the substance. We are oriented to applying a tiered approach, which assesses all possible parameters that compose the hazard evaluation of a chemical substance. 

Table II. Recently Observed Occupational Exposure Levels Work Place...

Exposure Levels in Humans. No data are available regarding the levels of PAHs in body tissues or fluids for populations living near hazardous waste sites. PAHs and their metabolites can be measured in the urine of exposed individuals. In workers exposed to PAHs, the PAH metabolite 1-hydroxypyrene has been detected in the urine at concentrations of 0-40 pg/g creatinine (Jongeneelen et al. 1985). No correlation was found between occupational exposure levels and urine levels, so it is not known whether urine metabolites could be detected following exposure to low levels of PAHs (as might be expected to occur in individuals living in the vicinity of hazardous waste sites). 

The subcommittee further concludes that in addition to inhalation exposures, the potential exists for a substantial contribution to the overall JP-8 exposure by the dermal route, including mucous membranes and the eyes, either by contact with vapors and aerosols or by direct skin contact with JP-8. It should be noted that earlier this year, the American Conference of Governmental Industrial Hygienists proposed a Threshold Limit Value for kerosene and j et fuels, as a total hydrocarbon vapor, of200 mg/m3.2 Also, ExxonMobil Biomedical Sciences, Inc., has set an occupational exposure level of 5 mg/m3 for kerosene and middle distillate fuel aerosols.3... 

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