Toxicants volatile, exposure

Liquid epoxy resin based on the reaction product of epichlorohydrin and bisphenol A or bisphenol F mild to moderate irritants mild to moderate sensitizers low volatility, exposure unlikely unless heated, sprayed, or spread over large unventilated surface low toxicity... 

Reactive diluents glycidyl ethers moderate to strong sensitizers moderate volatility, exposure possible low toxicity... 

Solvents acetone, methyl ethyl ketone (MEK), toluene, xylene, glycol, ethers, alcohol defats and dries skin some may be absorbed may carry other components through skin high volatility, exposure possible irritation central nervous system depression (e.g. dizziness, loss of coordination) low to high toxicity, longterm effects... 

The plant produced pesticides. An intermediate compound in this process is methyl isocyanate (MIC). MIC is an extremely dangerous compound. It is reactive, toxic, volatile, and flammable. The maximum exposure concentration of MIC for workers over an 8-hour period is 0.02 ppm (parts per million). Individuals exposed to concentrations of MIC vapors above 21 ppm experience severe irritation of the nose and throat. Death at large concentrations of vapor is due to respiratory distress. 

Molliave, L. (2000b) Volatile organic compounds and the sick building syndrome, in Environmental Toxicants. Human Exposures and Their Health Effects, 2nd edn (ed. M. Lippmann), John Wiley Sons, Inc., New York, USA, pp. 889-903. 

Reactive diluents Glycidyl ethers Moderate to strong sensitizers Moderate volatility, exposure possible Low toxicity... 

Solvents Acetone, methyl ethyl Defats and dries skin High volatility, exposure possible Low to high toxicity,... 

Very little information is available concerning the chronic toxicity of exposure to furan. Industrial use of furan is confined to closed systems due to the volatility of the compound therefore, the potential for direct exposure to furan is limited. The public exposure to commercial furan is minimal. 

II. Toxic dose. Because mycotoxins are not volatile, exposure would require inhalation of aerosolized spores, mycelial fragments, or contaminated substrates. The toxic inhaled dose of mycotoxin for humans is not known. Based on experimental data from single-dose in vivo studies, Stachybotrys chartarum spores (in-tranasally in mice or intratracheally in rats) high doses (more than 30 million spores/kg) can produce pulmonary inflammation and hemorrhage. The no-effect dose in rats (3 million ores/kg) corresponds to a continuous 24-hour exposure to 2.1 million spores/m for infants, 6.6 million spores/m for a school-age child, or 15.3 million spores/m for an adult. These spore concentrations are much higher than those measured in building surveys. 

PZT ceramics can be made by normal powder processing methods. The main difficulty is the high volatility of PbO. To retain as much PbO as possible sintering may be performed with the component surrounded by a lead-rich powder such as PZ and enclosed in a lidded crucible. Even with these precautions there is usually some (typically 2-3%) loss of PbO, which is compensated for by adding additional PbO to the starting batch. A note about safety lead is toxic and exposure to lead compounds has a cumulative effect. It is therefore necessary that evaporation is controlled. 

Typical examples of concentrations of regulated exposure are presented in Table 1.6 for three groups of toxic volatiles such as volatile organic compounds (VOCs), toxic industrial chemicals (TICs), and chemical warfare agents (CWAs). These examples demonstrate the need for gas-sensing capabilities with broad measurement dynamic ranges to cover two to four orders of magnitude in gas concentrations. 

Nickel carbonyl is volatile, has Htde odor, and is extremely toxic. Symptoms of dangerous exposure may not appear for several days. Effective medical treatment should be started immediately. The plant should be designed to ensure containment of nickel carbonyl and to prevent operator contact. 

Aromatic Hydrocarbons. These are the most toxic of the hydrocarbons and inhalation of the vapor can cause acute intoxication. Benzene is particularly toxic and long-term exposure can cause anemia and leukopenia, even with concentrations too low for detection by odor or simple instmments. The currendy acceptable average vapor concentration for benzene is no more than 1 ppm. PolycycHc aromatics are not sufftcientiy volatile to present a threat by inhalation (except from pyrolysis of tobacco), but it is known that certain industrial products, such as coal tar, are rich in polycycHc aromatics and continued exposure of human skin to these products results in cancer. 

The kidney is an important organ for the excretion of toxic materials and their metaboHtes, and measurement of these substances in urine may provide a convenient basis for monitoring the exposure of an individual to the parent compound in his or her immediate environment. The Hver has as one of its functions the metaboHsm of foreign compounds some pathways result in detoxification and others in metaboHc activation. Also, the Hver may serve as a route of elimination of toxic materials by excretion in bile. In addition to the Hver (bile) and kidney (urine) as routes of excretion, the lung may act as a route of elimination for volatile compounds. The excretion of materials in sweat, hair, and nails is usually insignificant. 

Parent substances and metaboHtes may be stored in tissues, such as fat, from which they continue to be released following cessation of exposure to the parent material. In this way, potentially toxic levels of a material or metaboHte may be maintained in the body. However, the relationship between uptake and release, and the quantitative aspects of partitioning, may be complex and vary between different materials. For example, volatile lipophilic materials are generally more rapidly cleared than nonvolatile substances, and the half-Hves may differ by orders of magnitude. This is exemplified by comparing halothane and DDT (see Anesthetics Insectcontholtechnology). 

Health and Safety Factors. The Material Safety Data Sheets provided by the suppUers should be consulted for each product. In general, products are aqueous emulsions with low levels of toxicity. Products with high solvent content have mostly been eliminated. Personnel handling the chemicals should always avoid contact of the products with skin and eyes, and avoid exposure to vapors if the product contains volatile components. 

Butylenes are not toxic. The effect of long-term exposure is not known, hence, they should be handled with care. Reference 96 Hsts air and water pollution factors and biological effects. They are volatile and asphyxiants. Care should be taken to avoid spills because they are extremely flammable. Physical handling requires adequate ventilation to prevent high concentrations of butylenes in the air. Explosive limits in air are 1.6 to 9.7% of butylenes. Their flash points range from —80 to —73° C. Their autoignition is around 324 to 465°C (Table 2). Water and carbon dioxide extinguishers can be used in case of fire. 

Toxicity. 1,1-Dichloroethane, like all volatile chlorinated solvents, has an anesthetic effect and depresses the central nervous system at high vapor concentrations. The 1991 American Conference of Governmental Industrial Hygienists (ACGIH) recommends a time-weighted average (TWA) solvent vapor concentration of 200 ppm and a permissible short term exposure level (STEL) of 250 ppm for worker exposure. The oral LD q of... 

In recent years, the use of solvent-borne adhesives has been seriously restricted. Solvents are, in general, volatile, flammable and toxic. Further, solvent may react with other airborne contaminants contributing to smog formation and workplace exposure. These arguments have limited the use of solvent-bome adhesives by different national and European regulations. Although solvent recovery systems and afterburners can be effectively attached to ventilation equipment, many factories are switching to the use of water-borne rubber adhesives, hot melts or 100% solids reactive systems, often at the expense of product performance or labour efficiency. 

In nonindustrial settings, MCS substances are the cause of indoor air pollution and are the contaminants in air and water. Many of the chemicals which trigger MCS symptoms are known to be irritants or toxic to the nervous system. As an example, volatile organic compounds readily evaporate into the air at room temperature. Permitted airborne levels of such contaminants can still make ordinary people sick. When the human body is assaulted with levels of toxic chemicals that it cannot safely process, it is likely that at some point an individual will become ill. For some, the outcome could be cancer or reproductive damage. Others may become hypersensitive to these chemicals or develop other chronic disorders, while some people may not experience any noticeable health effects. Even where high levels of exposure occur, generally only a small percentage of people become chemically sensitive. 

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