Materials , toxic hazard

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. 

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. 

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. 

The preparation of soils for crops, planting, and tilling raises dust as a fugitive emission. Such operations are shll exempt from air pollution regulations in most parts of the world. The application of fertilizers, pesticides, and herbicides is also exempt from air pollution regulations, but other regulations may cover the drift of these materials or runoff into surface waters. This is particularly true of the materials are hazardous or toxic. 

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. 

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

Special areas for the handling of highly toxic, hazardous and sensitising materials. 

Explosive and Toxic Hazard Materials page 370 (MeidI, 1970)... 

Distances for storage of explosives Explosive and Toxic Hazard Materials page 370 (MeidI, 1970) Safe Handling Requirements during Explosive, Propellant and Pyrotechnic Manufacture (HSE, SIR 31)... 

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. 

As these strategies are brought to fruition, there remains one related issue the determination of a smoke s potential harm per mass of material burned, i.e., the toxic potency of smoke. Accurate measurement of this key characteristic of fire smoke permits a more quantitative determination of the fire s toxic hazard which includes other factors as discussed below. Toxic potency assessment also tells us whether a small fire will produce smoke so toxic that only a small amount will kill. The presence of such "supertoxicants" has been a major topic of discussion within the fire community. 

Babrauskas, V., Toxic Hazard from Fires a Simple Assessment Method, Proceedings of conference on "Fire Control the Heat. Reduce the Hazard. Queen Mary College Fire and Materials Centre and Fire Research Station, London, England, 1988, p 1-10. 

Toxicity. There is only one Member State (Germany) having a test which is used to assess toxic hazards of combustion gases. The test is used mainly to evaluate non-combustible materials and is based on bio-assay techniques. The philosophies of other countries consider non-combustible materials as presenting no, or negligible toxic hazard. 

Viscous liquid with a strong fishy odor. This material is hazardous through inhalation and ingestion, and produces local skin/eye impacts. Hydrolysis product TR is formed when there is only a limited amount of water present. It is highly reactive and toxic. 

The combination of toxic hazard and high price (itself in part due to the extra measures needed in production processes to ensure the workers safety) has been an effective brake on commercial development of beryllium chemistry. Where possible substitute, albeit less effective, materials are often used titanium as an alternate lightweight metal or carbon fiber composites, phosphor-bronzes in place of beryllium alloys, aluminum nitride in place of BeO (1). 

Mond Index Material factor Special material hazards General process hazards Special process hazards Quantity factor Layout hazards Toxicity hazards... 

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