Toxic hazard rating

Toxicity information Toxic hazard rating Hygiene standard (e.g. OLE, TLV) Maximum allowable concentration (MAC) Lethal concentration (LC50) Lethal dose (LD50) ... 

Toxic Hazard Rating Table Significance Description... 

In general, aminophenols are irritants. Their toxic hazard rating is slight to moderate and their acute oral toxicities in the rat (LD50) are quoted as 1.3 g/kg, 1.0 g/kg, and 0.373 gtkg body weight for the 2-, 3-, and 4-isomer, respectively. 

Toluene, a colorless liquid by itself, is the active ingredient in almost all types of plastic cement. According to the Toxic Hazard Rating Code, a guide to industrial chemicals and potential hazards, toluene is dangerous, but is not the immediate-brain damage chemical that we have been lead to believe it is. 

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. 

Both approaches are useful and they are also complementary because it is important to know where a chemical that may be best in its class falls out with respect to hazard. For example, a surfactant that is best in its class will be rapidly biodegradable, but most surfactants have some aquatic toxicity because they are surface active. However, surfactants as a class are typically close to the green end of the hazard spectrum because they tend to have low hazard ratings for most other endpoints. It is also possible to have chemicals that are best in their class but that are still problematic. For example, some dioxin congeners are less toxic than others but one would not presume that a dioxin congener that is best in its class is green . Concurrent use of the best in class approach with the absence of hazard approach is also important because it drives continual advancement within a class toward the ideal green chemistry. Once innovation occurs and a chemical or product is developed that meets the same or better performance criteria with lower hazard, what was once considered best in class shifts. 

GD is a lethal anticholinesterase agent. Although it is primarily a vapor hazard, its toxic hazard is high for inhalation, ingestion, and eye and skin exposure. Its rate of detoxification in the body is low. 

Furthermore, it has been shown that the time period until ignition occurs, in the Cone calorimeter, is proportional to the inverse of the flame spread rate [16]. The Cone calorimeter can also be used to provide the mass loss rate information required for the simplified classification into categories of toxic hazard [1] quick toxic hazard assessment. Thus, the NBS Cone calorimeter is a very useful tool to overcome some of the disadvantages associated with measuring a single property at a time. 

Chemical Exposure Index (CEI) (Chemical Exposure Index, 1994 Mannan, 2005, pp. 8/22-8/26.) The CEI provides a method of rating the relative potential of acute health hazard to people from possible chemical release incidents. It may be used for prioritizing initial process hazard analysis and establishing the degree of further analysis needed. The CEI also may be used as part of the site review process. The system provides a method of ranking one risk relative to another. It is not intended to define a particular containment system as safe or unsafe, but provides a way of comparing toxic hazards. It deals with acute, not chronic, releases. Flammability and explosion hazards are not included in this index. To develop a CEI, information needs include... 

Chronic in vivo toxicity studies are generally the most complex and expensive studies conducted by a toxicologist. Answers to a number of questions are sought in such a study, notably if a material results in a significant increase in mortality or in the incidence of tumors in those animals exposed to it. But we are also interested in the time course of these adverse effects (or risks). The classic approach to assessing these age-specific hazard rates is by the use of life tables (also called survivorship tables). 

Selected entries from Methods in Enzymology [vol, page(s)] Types of organophosphorus inhibitors, 11,686-688 toxicity hazards, 11,688 purity and analysis, 11,688 solutions of organophosphorus compounds, 11,689 estimation of specific radioactivity of organophosphorus compounds, 11,689-690 method for estimating phosphorus content, 11,691 reactions with enzymes, 11,691 -701 [rate constants, 11,692 phosphorylation of chymotrypsin, 11, 694-696 identification of phosphoryl and phosphonyl peptides,... 

Methanol docs not pose an undue toxicity hazard if handled in well-vemilaled areas, and is rated as a slight health hazard by the National Fire Protection Association (NFPAt. http //www.nfpa.org/. 

Sax (Ref 4) considers the trisulfide s hazard rating and toxicity to be the same as that of arsenic disulfide (qv)... 

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. 

Using this EHS method, formaldehyde, dioxane, formic acid, acetonitrile and acetic acid have high (environmentally poor) scores (Figure 1.1). Formaldehyde has acute and chronic toxicity, dioxane is persistent and the acids are irritants. Methyl acetate, ethanol and methanol have low scores, indicating a lower hazard rating. 

Sodium thiosulfate is a skin, eye, nose, and throat irritant. It is moderately toxic by an intravenous route. It has a NFPA rating of 1, 0, and 0 for health, fire, and reactivity, respectively. (Hazard rating is from 0 to 4, with 0 indicating no hazard and 4 indicating extreme hazard.) Results from toxicity studies indicate that sodium thiosulfate is not very toxic to aquatic species (16). For Ceriodaphnia, the 24 and 48 h LC q values are 2.5 and 0.85 g/L, respectively. For Daphnia, these values are 2.2 and 1.3 g, respectively. For... 

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