Exposure by inhalation

Undiluted DMAMP, AMP-95, and AB cause eye bums and permanent damage, if not washed out immediately. They are also severely irritating to the skin, causing bums by prolonged or repeated contact. Of these three aLkanolarnines, only AMP has been studied in subchronic and chronic oral studies. The principal effect noted was the action of AMP on the stomach as a result of its alkalinity. The no-observed-effect level (NOEL) in a one-year feeding study in dogs was 110 ppm in the diet. In general, the low volatility and appHcations for which these products are used preclude the likelihood of exposure by inhalation. 

The threshold limit value—time integrated average, TLV—TWA, of chlorine dioxide is 0.1 ppm, and the threshold limit value—short-term exposure limit, STEL, is 0.3 ppm or 0.9 mg /m of air concentration (87,88). Chlorine dioxide is a severe respiratory and eye irritant. Symptoms of exposure by inhalation include eye and throat irritation, headache, nausea, nasal discharge, coughing, wheezing, bronchitis, and delayed onset of pulmonary edema. Delayed deaths occurred in animals after exposure to 150—200 ppm for less than one hour. Rats repeatedly exposed to 10 ppm died after 10 to 13 days of exposure. Exposure of a worker to 19 ppm for an unspecified time was fatal. The ingested systemic effects of low concentration chlorine dioxide solutions are similar to that of chlorite. 

Limitation of the use of respiratory protection to those situations where control of exposure by inhalation cannot be controlled by other means. 

In exposures by inhalation of airborne materials, the dose is the concentration multiplied by the time (CT), and is roughly a constant for any given material and specified effect. The CT value can be used to provide a rough approximation of other combinations of concentration and time which would have about the same effect. Although this concept must be used very cautiously and cannot be applied at extreme conditions of either concentration or time, it is most important in setting limits for airborne contaminants and physical agents in respect to environmental exposures. The worker is exposed for various periods of time, day after day, to the... 

CFN (1992). Workplace atmospheres — Guidance for the assessment of exposure by inhalation to chemical agents for comparison with limit values and measurement strategy. EN 689. 

Exposure by inhalation The toxic exposure of the body due to breathing contaminated air. 

As a result of volatilization, significantly elevated indoor air levels of trichloroethylene can occur in homes that use water supplies contaminated with trichloroethylene (Andelman 1985a). The transfer of trichloroethylene from shower water to air in one study had a mean efficiency of 61% which was independent of water temperature (McKone and Knezovich 1991). The study authors concluded that showering for 10 minutes in water contaminated with trichloroethylene could result in a daily exposure by inhalation comparable to that expected by drinking contaminated tap water. Another study using a model shower system found that, in addition to shower spray, shower water collecting around the drain could be an important source of volatilized trichloroethylene, and the fraction volatilized could be affected by spray drop size and flow rate (Giardino et al. 1992). 

Francisella tularensis is very infectious. A small number (10-50 or so organisms) can cause disease. If F. tularensis were used as a weapon, the bacteria would likely be made airborne for exposure by inhalation. People who inhale an infectious aerosol would generally experience severe respiratory illness, including life-threatening pneumonia and systemic infection, if they are not treated. The bacteria that cause tularemia occur widely in nature and could be isolated and grown in quantity in a laboratory, although manufacturing an effective aerosol weapon would require considerable sophistication. 

I, 1,1,2-tetrafluoroethane (HFC134a) in rat following a single exposure by inhalation. Xenobiotica 23 719—729. 

Data concerning concentrations of phenol in ambient air are insufficient to estimate the potential for exposure by inhalation. However, it is known that the smoke of 1 nonfilter cigarette contains 60-140 g phenol, while levels of phenol range from 19-35 g in the smoke of filter-tipped cigarettes, and from 24-107 g in the smoke of cigars (IARC 1986 NCI 1998). Indoor environments polluted with tobacco smoke contain measurable amounts of phenol (Guerin et al. 1982). 

Target Tissues. The Reitz model only applies to the metabolism of chloroform and the induction of cytotoxicity in liver tissue following exposure by inhalation, drinking water, and gavage routes using rat and mouse data. 

Table A-1. Corley PBPK Model for Chloroform to Simulate Mouse Exposure by Inhalation...

Acute inhalation toxicity is the total of adverse effects caused by a substance following a single, uninterrupted exposure by inhalation over a short period of time to an airborne substance. Eor testing, a fixed duration of exposure of 4h is generally recommended in the OECD TG 403. 

It should be noted that the TTC concept at present is limited to oral exposure as the databases behind the concept do not include studies using dermal application or exposure by inhalation. 

Acute-Duration Exposure. No data are available on the effects of hexachlorobutadiene in humans after acute exposure by inhalation, oral, and dermal routes. Hexachlorobutadiene (50 ppm) was lethal in mice after acute (5 days) inhalation exposure and caused irritation of the nasal cavities following 15 minute exposures to concentrations of 15 ppm or greater (de Ceaurriz et al. 1988 NIOSH 1981). Because sufficient data are not available to determine target organs or determine critical effect levels, an acute inhalation MRL cannot be determined. 

TLV The TLV or Threshold Limit Value refers to a safe level of exposure by inhalation. The definition was established by the American Conference of Governmental Hygienists. There are several variations or criteria levels for the TLV. As an example, hydrogen sulfide has a TLV for short-term exposure limits (STEL) of 15 minutes of only 5 ppm. Comparing this to the TLV-STEL of 400 ppm for carbon monoxide provides an indication of the need to be extremely careful when H2S is suspected. Under OSHA Standards, and particularly on MSDS (Material Safety Data Sheets) compounds are associated with a time weighted average (TWA) TLV, which is the allowable concentration for an 8-hour continuous exposure period. For firefighting purposes, the short-term exposure is likely more realistic. 

Nemec M, Holsen J, Naas D, et al. 1992. The developmental toxicity of FM-100 in the rat and rabbit following repeated exposure by inhalation. Teratology 45(5) 475-476. 

Exposure by inhalation to methyl chloride causes fetal growth retardation and impaired male reproductive capacity in rats and malformations of the heart in fetal mice (lARC, 1986). The preimplantation losses described in rats in which the males were exposed to 6300 mg/m methyl chloride for 6 h per day for five days were due to a failure of fertilization rather than preimplantation embryonic death. A concentration of 2100 mg/m3 had no effect upon fertilization (Working Bus, 1986). 

Maternally toxic or near-toxic amounts of xylene have been associated with malformations in mice after oral administration and with embryotoxicity in rabbits, rats and mice after exposure by inhalation (lARC, 1989). 

Chlorodifluoromethane causes malformations of the eyes of fetal rats, but has no reproductive effect in male rats and does not cause prenatal toxicity in rabbits following exposure by inhalation (lARC, 1986). 

In the EU pure cadmium sulfide is labelled with the symbol T (Toxic) and the Risk phrases 22-40-48/23/25 - Harmful if swallowed. Possible risks of irreversible effects. Toxic Danger of serious damage to health by prolonged exposure by inhalation and if swallowed. 

The toxic effects of chronic exposure to cadmium differ somewhat with the route of exposure. The kidney is affected following either pulmonary or gastrointestinal exposure marked effects are observed in the lungs only after exposure by inhalation. 

Worker exposure to alkanes, especially the lower-molecular-mass compounds, is most likely to come from inhalation. In an effort to set reasonable values for the exposure by inhalation of vapors of solvents, hydrocarbons, and other volatile organic liquids, the American Conference of Governmental Industrial Hygienists sets threshold limit values (TLVs) for airborne toxicants.1 2 The time-weighted average exposure (E) is calculated by the formula... 

People who smoke and those who have a history of lung disease may be at an increased risk of exposure by inhalation. Studies show that inhalation of dust from barium salts produces a mild, but lengthy, inflammatory response in the lungs of rats (Huston et al. 1952). A benign pneumoconiosis has been noted in cases of chronic, low-level exposure in humans (Doig 1976). Smoking and lung diseases may increase the intensity of this response in affected individuals. 

In the evaluation of toxic characteristics of an inhalable environmental chemical (e.g., carbon monoxide, volatile chemical, or aerosol/particulate), determination of acute inhalation toxicity is an initial study step. It provides information on health hazards likely to arise from short-term exposure by inhalation. Data from an acute test help to establish a dose regimen in subchronic (and other) studies, and may provide additional information on a chemical s mode of toxic action. 

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