Toxic hazard rating limits

Methanol does not pose an undue toxicity hazard if handled in weU-ventilated areas, and is rated as a slight health hazard by the National Fire Protection Association (NFPA). The TLV is 200 ppm with a STEL of 250 ppm, and the limit which is immediately dangerous to Hfe and health is 25,000 ppm. Accidental ingestion is immediately treated by inducing vomiting, followed by adrninistration of sodium bicarbonate. Rinsing with water is effective in treating external exposure. 

Measurement of exposure can be made by determining levels of toxic chemicals in human serum or tissue if the chemicals of concern persist in tissue or if the exposure is recent. For most situations, neither of these conditions is met. As a result, most assessments of exposure depend primarily on chemical measurements in environmental media coupled with semi-quantitative assessments of environmental pathways. However, when measurements in human tissue are possible, valuable exposure information can be obtained, subject to the same limitations cited above for environmental measurement methodology. Interpretation of tissue concentration data is dependent on knowledge of the absorption, excretion, metabolism, and tissue specificity characteristics for the chemical under study. The toxic hazard posed by a particular chemical will depend critically upon the concentration achieved at particular target organ sites. This, in turn, depends upon rates of absorption, transport, and metabolic alteration. Metabolic alterations can involve either partial inactivation of toxic material or conversion to chemicals with increased or differing toxic properties. 

If the material released to the atmosphere is not ignited, the spill can be accompanied by flash vaporization, liquid entrainment, and/or liquid accumulation (with pool formation and evaporation), and associated vapor dispersion. Absence of an immediate ignition source allows a vapor cloud to form as the vapors disperse downwind. A portion of this vapor cloud may be flammable, and if the gas has any toxic components, it can also pose a toxic hazard. The downwind extent of the flammable hazard depends on the size of the release, the upper and lower flammability limits of the material, and the air entrainment rate. 

In general, the interactions between xenobiotics and ecosystem constituents are reversible and tend to establish steady states conditioned by the rate-limiting steps. The reversibility applies, of course, only to the interactions at the molecular level, not to the (long-term) impacts on ecosystems. With respect to hazard and risk assessment, parameters regarding the distribution (e.g. bioconcentration and soil sorption), the reactivity (e.g. degradation) and the toxicity (e.g. aquatic species such as fish, crustaceans, algae) are considered. For the description of the chemicals, mostly structurally derived physico-chemical properties are used, among which the most prominent is the 1-octanol/water partition coefficient. The log parameter quanti-... 

Fire Hazards - Flash Point Not flammable Flammable Limits in Air (%) Not flammable Fire Extinguishing Agents Not pertinent Fire Extinguishing Agents Not To Be Used Not pertinent Special Hazards of Combustion Products Toxic oxides of nitrogen may form in fire Behavior in Fire Sealed containers may burst as a result of polymerization Ignition Tenqterature Not pertinent Electrical Hazard Not pertinent Burning Rate Not pertinent. 

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