Toxicity hazards

Factors which may affect the cost of coal upgrading are environmental considerations such as toxicity, hazardous waste disposal, and carcinogenic properties (131). These and other environmental problems from process streams, untreated wastewaters, and raw products would figure significantly into the cost of commercialization. 

C. C. Haun and E. R. Kiokead, Chronic Inhalation Toxicity ofHydra ne, University of California, Irviue, Toxic Hazards Research Unit, Dayton, Ohio, Jan. 1975. 

P. J. Canney and P. T. Schaefer, in M. D. LaGrega and L. K. Hendrian, eds.. Proceedings of the 15th Toxic Hazardous Waste Processing Mid-Atlantic Industrial Waste Conference, Butterworth, U.K., 1983, pp. 277—284. 

Environmental Factors. The control, recovery, and disposal of mercury-bearing waste products are as important to the mercurials industry as the manufacturing process. The difficulties involved in removing mercury from waste-product streams and the problems of recovery or disposal have resulted in a substantial reduction in the number of manufacturers of mercury compounds as well as in the variety of mercury compounds being manufactured. Moreover, the manufacturing process used for a mercury compound may not necessarily be the most efficient or economical. Rather, the choice may depend on the nature of the by-products, the toxic hazard of the process, and the ease of recovery of the mercury from the waste-product stream. 

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. 

Although ammonium nitrate does not itself bum, it is a strong oxidizer capable of supporting the combustion of numerous substances when heated. It can support and intensify a fire even when air is excluded. Fires involving ammonium nitrate also present a toxic hazard from the release of nitrogen oxides, even though the soHd itself is generally considered not to be toxic. 

Health and Safety Factors. The strontium ion has a low order of toxicity, and strontium compounds are remarkably free of toxic hazards. Chemically, strontium is similar to calcium, and strontium salts, like calcium salts, are not easily absorbed by the intestinal tract. Strontium carbonate has no commonly recognized hazardous properties. Strontium nitrate is regulated as an oxidizer that promotes rapid burning of combustible materials, and it should not be stored in areas of potential fire hazards. 

Process Hazard Analysis (PHA) (Dowell, 1994, pp. 30-34.) The OSHA rule for Process Safety Management (PSM) of Highly Toxic Hazardous Chemicals, 29 CFR 1910.119, part (e), reqmres an initial PHA and an update every five years for processes that handle listed chemicals or contain over 10,000 lb (4356 kg) of flammable material. The PHA must be done by a team, must include employees such as operators and mechanics, and must have at least one person skilled in the methodology employed. Suggested methodologies from Process Safety Management are listed in Table 26-1. 

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. The procedure focuses on the... 

Toxicity and Toxic Hazard There is a difference between toxicity and toxic hazard ... 

Toxic hazards may be caused by chemical means, radiation, and noise. Routes of exposure are (1) eye contact, (2) inhalation, (3) ingestion, (4) skin contact, and (5) ears (noise). An Industrial Hygiene Guide (IHG) is based on exposures for an 8-h day, 40-h week, and is not to be used as a guide in the control of health hazards. It is not to be used as a fine hne between safe and dangerous conditions. 

A material that has a high toxicity does not necessarily present a severe toxic hazard. For example, a ton of lead arsenate spilled in a busy street is unhkely to poison members of the public just a short distance from the spiU, because it is not mobile. It could be carefully recovered and removed and would present a low risk to the gener pubhc, even though it is extremely toxic. On the other hand, a ton of liquefied chlorine spilled on the same street could become about 11,000 fF of pure gas. The IDLH for chlorine is 25 ppm. This is a concentration such that immediate action is required. Thus, the one ton of chlorine, if mixed uniformly with air, could create a cloud of considerable concern, having a volume of about 4.4 X 10 fF or a sphere 770 ft in diameter. This could quickly spread over downwind areas and... 

Instrumentation (Arthur D. Little, Inc., and Levine, 1986.) Instrument systems are an essential part of the safe design and operation of systems for storing and handling highly toxic hazardous materials. They are key elements of systems to eliminate the threat of conditions that could result in loss of containment. They are also used for early detection of releases so that mitigating ac tion can be taken before these releases result in serious effects on people in the plant or in the public sector, or on the environment. 

Variation in waste by batch. Feed variability to downstream waste processing equipment. Possibility of reaction in waste streams, flammable/ toxic hazard. 

CCPS G-3. 1988. Guidelines for Safe Storage and Handling of High Toxic Hazard Materials. American Institute of Chemical Engineers, Center for Chemical Process Safety, New York. 

Dailey, W. V. 1976. Area Monitoring for Elammable and Toxic Hazards. Loss Prevention Manual, Vol. 10. American Institute of Chemical Engineers, New York. 

Immediately after the running test, any compressor intended for toxic, hazardous, flammable, or hydrogen-rich service should be gas tested with an inert gas to the maximum seal design pressure. The test is held at least 30 minutes and the casing and its joints checked for leaks, using a soap bubble method or other suitable means for leak detection. When no leaks are detected, the compressor will be considered acceptable. 

Reactions in bulk are used commercially but careful control of temperature is required. Polymerisation in a suitable solvent will dilute the concentration of reacting material and this together with the capability for convective movement or stirring of the reactant reduces exotherm problems. There is now, however, the necessity to remove solvent and this leads to problems of solvent recovery. Fire and toxicity hazards may also be increased. 

Lin, S. H. and Chen, Y. V., Adsorption and desorption characteristics of 1,1-dichloro-1-fluoroethane by granular activated carbon and activated carbon fiber, J. Environ. Sci. Health, Part A Toxic / Hazard Subst. Environ. Eng., 1996,31(6), 1279 1292. 

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

Indicators of toxicity hazards include LD50, LC50, plus a wide range of in vitro and in vivo techniques for assessment of skin and eye indtation, skin sensitization, mutagenicity, acute and chronic dermal and inhalation toxicity, reproductive toxicology, carcinogenicity etc. 

Table 7.4 Toxic hazards from incompatible chemical mixtures...

Polymerization Exothermic reaction which, unless carefully controlled, can run-away and create a thermal explosion or vessel overpressurization Refer to Table 7.20 for common monomers Certain processes require polymerization of feedstock at high pressure, with associated hazards Many vinyl monomers (e.g. vinyl chloride, acrylonitrile) pose a chronic toxicity hazard Refer to Table 7.19 for basic precautions... 

Particle size distribution (R) Design of separation equipment Toxic hazard Environmental impact Wide range including Microscopy Holography Light scatter Sieving... 

Meidl, J.H. (1970) Explosive and Toxic Hazardous Materials, Glencoe, Westerville, OH. 

Richardson, M.L. (ed). (1986) Toxic Hazard Assessment of Chemicals, The Royal Society of Chemistry, London. 

Chromic acid concentrations m air (superseded by MDHS 52/3 (1998JJ Petroleum based adhesives m building operations Arsenic toxic hazards and precautions Spraying of highly flammable liquids... 

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