Concentration lethal

On the other hand, if the hazard is toxicity, process alternatives can be compared by assessing the mass of toxic material that would enter the vapor phase on release from containment, weighting the components according to their lethal concentration. 

Va2o-64, ALC (approx lethal concentration) Va2o-67, LC q. Va2o-64, -52, -88, ALD (approx lethal dose) Va2o-67, LD. See text for chemical names and stmctures. 

Repeated exposures of animals to high (near-lethal) concentrations of vapors result in inflammation of the respiratory tract, as weU as degenerative changes in the Hver, kidneys, and heart muscle. These effects arise at concentrations far above those causing irritation. Such effects have not been reported in humans. The low odor threshold and irritating properties of acrylates cause humans to leave a contaminated area rather than tolerate the irritation. 

Laboratory experiments using rodents, or the use of gas analysis, tend to be confused by the dominant variable of fuel—air ratio as well as important effects of burning configuration, heat input, equipment design, and toxicity criteria used, ie, death vs incapacitation, time to death, lethal concentration, etc (154,155). Some comparisons of polyurethane foam combustion toxicity with and without phosphoms flame retardants show no consistent positive or negative effect. Moreover, data from small-scale tests have doubtful relevance to real fine ha2ards. 

Approximate lethal concentration, inhalation by tats, 4 h exposure unless noted otherwise. 

Properties. Properties of perfluoropropyl vinyl ether [1623-05-8] (PPVE), a colorless, odorless Hquid (mol wt 266) are shown in Table 1. Perfluoropropyl vinyl ether is an extremely flammable Hquid and bums with a colorless flame. It is significantly less toxic than hexafluoropropylene the average lethal concentration (ALC) is 50,000 ppm (10). 

Health and Safety Factors. VDE is a flammable gas its combustion products are toxic. Liquid VDE on contact with the skin can cause frostbite. Acute inhalation toxicity of VDE is low median lethal concentrations (LC q) for rats were 128,000 ppm after a single 4-h exposure (52) and 800,000 ppm after a 30-min exposure (53). Cumulative toxicity is low exposure of rats and mice at levels of up to 50,000 ppm for 90 days did not cause any... 

The LC q (lowest possible lethal concentration) has been reported to be 23 ppm for a 30 min exposure time (mouse), 53 ppm for an exposure time of 100 min (rat, rabbit, and guinea pig), and 200 ppm for an exposure time of 10 min (monkey). No toxic effects were reported upon exposure to 1 ppm for 7 h/d over 55 days. The oral LD q (rat) of ketene is 1300 mg/kg, the low level of toxicity probably being due to the almost immediate formation of acetic acid and other acetates in the digestive tract. 

Propylene oxide is a primary irritant, a mild protoplasmic poison, and a mild depressant of the central nervous system. Skin contact, even in dilute solution (1%), may cause irritation to the eyes, respiratory tract, and lungs. Propylene oxide is a suspected carcinogen in animals. The LC q (lowest lethal concentration by inhalation in tats) is 4000 mg/kg body weight. The LD q (oral) is 930 mg/kg. The LD q (dermal) is 1500 mg/kg. The TWA (8-h exposure) is 100 ppm and the STEP (15-min exposure) is 150 ppm. 

Health, Safety, and Environmental Factors. Sulfur dioxide has only a moderate acute toxicity (183). The lowest pubHshed human lethal concentration is 1000 ppm for 10 months. The lowest pubHshed human toxic concentration by inhalation is 3 ppm for 5 days or 12 ppm for 1 hour. The lowest pubHshed human lethal concentration is 3000 ppm for 5 months. In solution (as sulfurous acid), the lowest pubHshed toxic dose is 500 flg/kg causing gastrointestinal disturbances. Considerable data is available by other modes of exposure and to other species NIOSH standards are a time-weighted average of 2 ppm and a short-term exposure limit of 5 ppm (183). 

Toxicity parameters are defined as follows LD q = lethal dose 50% kill LCLq = lowest pubHshed lethal concentration LC q = lethal concentration 50% kill LDLq = lowest pubHshed lethal dose. 

The use of black cyanide as a fumigant and rodenticide makes use of the atmospheric humidity action that Hberates hydrogen cyanide gas. It can only be used effectively ia confined spaces where hydrogen cyanide builds up to lethal concentrations for the particular appHcation. Black cyanide is also used ia limited quantities ia the production of pmssiates or ferrocyanides (see Iron compounds). 

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

The LC50 is the lethal concentration of chemical (e.g. in air or water) that will cause the death of 50% of the sample population. This is most appropriate as an indicator of the acute toxicity of chemicals in air breathed (or in water, for aquatic organisms). Table 5.11 illustrates the use of LD50 values to rank the toxicity of substances. 

LCio 430 This concentration is die lowest published lethal concentration for a hmnmi over a 10... 

LCiu 30,000 This concentration is tlie lowest published lethal concentration for a human over a 5-minute exposure. 

TC.o 20 This concentration is tlic lowest published lethal concentration causing toxic effects (irritation). 

Lethal Concentration 50 (LCso) A calculated concentration of a chemical in air to hich exposure for a specific length of time is expected to cause death in 50% of a defined experimental animal population. 

Median Lethal Concentration (LC) The concentration of a to.xicant lethal to one half of a test population. 

To quantify the effect of a chemical on a population, groups of organisms are exposed to different concentrations of the chemical for a predetermined interval. The concentration at which 50% of the test population responds is known as the EC u (effective concentration 50%) when death is the measured response, it is called the (lethal concentration 50%). 

There are several significant permit conditions. As with all other OCS permits, the discharge of oil-based muds is prohibited. Similarly, the permit does not unconditionally authorize the discharge of any of the eight generic muds. Their discharge is subject to limitations on additives. To monitor the use of mud additives, the permit requires the additive not to drop or to decrease the 96-hr median lethal concentration (LC ) test below 7,400 ppm on the basis of the suspended particulate phase or 740 ppm for the whole mud. This parameter is based on a test of Generic Mud 8, which is formulated with 5% mineral oil. 

Elemental bromine is a readily evaporating liquid (pBr at 1 °C = 0.23 bar) with high reactivity. Because of the good solubility of Br2 in lipids, its aggressive and toxic properties affect skin and mucous membranes (bronchi). The MAK value of elemental Br2 is defined as 0.1 ppm (0.7 mg m 3), while the sense of smell is affected at a value of 0.01 ppm. The lethal concentration (around 100-200 ppm) is reached for example, by twice the MAK value, 5 min, eight times per working unit [91, 92]. 

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