Hazardous concentration

After reading the article by Kelly on peroxidizables (see Table 13-2 reference), state the minimum hazardous concentrations of peroxides in solution with organic chemicals. 

Static-dissipative (antistatic) material One with an electrical resistivity that is low enough to make it incapable of accumulating hazardous concentrations of static charges when grounded. 

Enclosures, even partial enclosures, containing equipment handling flammable, combustible, ortoxic materials may permit the accumulation of hazardous concentrations of these materials within the enclosure, potentially resulting in fire, explosion, or personnel exposure. Where the possibility of a flammable spill or release within an enclosure exists, the enclosure design should include a relevant selection from the following features noncombustible construction, adequate ventilation, drainage, appropriate electrical classification, flammable vapor detection, isolation and alarm, and internal automatic sprinkler or water spray protection. 

Arsine is nonirritating with a garlic-like odor. Warning properties of exposure to hazardous concentrations are inadequate. ... 

The odor is recognized by most people at 5 ppm, but tolerance may be readily acquired. The irritating property may not be sufficient to protect from hazardous concentrations. 

Carbon disulfide is foul-smelling, but the odor is not sufficient to give adequate warning of hazardous concentrations. 

Inhalation of appreciable amounts of cresol vapor is unlikely under normal conditions because of the low vapor pressure however, hazardous concentrations may be generated at elevated temperatures. Seven workers exposed to cresol vapor at unspecified concentrations for 1.5-3 years had headaches, which were frequently accompanied by nausea and vomiting. Four of the workers also had elevated blood pressure, signs of impaired kidney function, blood calcium imbalance, and marked tremors. Eight of ten subjects exposed to 1.4 ppm o-cresol vapor experienced upper respiratory tract irritation. ... 

DETA has a strong ammonia-like odor, but it does not provide adequate warning of hazardous concentrations. ... 

Ethylene is not irritating to the skin and eyes. The gas has a faintly sweet odor that probably does not provide adequate warning of hazardous concentrations. Owing to the highly flammable and explosive characteristics of ethylene, it should be handled cautiously. ... 

The low vapor pressure of phenyl ether and its easily detectable odor should prevent exposure to hazardous concentrations. ... 

Pyridine has an unpleasant odor detectable at Ippm the odor is objectionable to unacclimatized individuals at 10 ppm but does not provide sufficient warning of hazardous concentrations because olfactory fatigue occurs quickly. ... 

Aldenberg T, Jaworska J. 2000 Uncertainty of the hazardous concentration and fraction affected for normal species sensitivity distrihutions. Ecotox Env Saf 46 1-18. 

Aldenberg, T., Slob, W., (1993). Confidence limits for hazardous concentrations based on logistically 13 distributed NOEC toxicity data. Ecotoxicology and Environmental Safety, 25, 48-63. 

Frederick (1981) concluded that screen printers are exposed to hazardous concentrations of isophorone and other solvents (xylene, methylene chloride, and toluene). 

Waste facilities should be designed to prevent explosions in sewer systems and typically are comprised of suitable traps, vents, dean-outs, collecting chambers, etc. Flammable gas detectors are installed in sewers to warn of hazardous concentrations, and inert gas blanketing of closed process sumps generally is advisable. 

Student s t-test is frequently used in statistical evaluations of environmental chemical data. It establishes a relationship between the mean (x) of normally distributed sample measurements, their sample standard deviation (,v), and the population mean (p). Confidence intervals may be calculated based on Student s t-test (Equation 10). The upper limit of the confidence interval is compared to the action level to determine whether the sampled medium contains a hazardous concentration of a pollutant. If the upper confidence limit is below the action level, the medium is not hazardous otherwise the opposite conclusion is reached. 

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