Toxicity of gases

Some concerns have been raised regarding potential toxicity of gases generated during fire conditions. 

The respiratory toxicity of gases and vapors is determined for several different physical and chemical properties. These factors include (1) chemical dose, (2) water solubility (hydrophilicity versus lipophilicity), and (3) chemical reactivity. 

The subcommittee recommends that the effects of altered environmental conditions (e.g., pressure, temperature, and humidity) on the toxicity of the gases on a disabled submarine be studied. Because fires on a disabled submarine will generate a large amount of particulate matter, research should be conducted on the effects of particles on the toxicity of gases. 

Wilkins ES and Wilkins MG (1985.) Review of toxicity of gases emitted from combustion pyrolysis of municipal and industrial wastes. Journal of Environmental Science and Health - Part A 20(2). 

This classic in the field of pharmacology provides detailed information on anatomy and functions of the autonomic nervous system. Although primarily concerned with drugs and how they act upon the body, there are also excellent sections on the toxicity of gases and vapors and heavy metals. Goodman and Gilman thoroughly evaluate many of the more widely used compounds utilized by the pharmaceutical industry. 

Yamamoto, K., and Y. Yamamoto. 1971. Toxicity of gases released by polyurethane foams subjected to sufficiently high temperature. Nippon Hoigaku Zasshi 25(4) 303-14. 

Hazard Zone means one of four levels of hazard (Hazard Zones A through D) assigned to gases, as specified in 173.116(a) of this subchapter, and one of two levels of hazards (Hazard Zones A and B) assigned to liquids that are poisonous by inhalation, as specified in 173.133(a) of this subchapter. A hazard zone is based on the LC50 value for acute inhalation toxicity of gases and vapours, as specified in 173.133(a). US 171.8... 

Toxicity of gases evolved from burning plastics... 

Hilado, C. J. Huttlinger, P. A. Toxicity of gases from polymer blends and mixtures. J, Elastomers and Plastics, 12, 219 (1980)... 

Sato, Y., Tsuda, Y, (1995) Toxicity of Gases from Full-scale Room Fires involving Fire Retardant Content, J. Fire Sci., 13, 1, 23-42. 

The esters of monofluorophosphoric acid are of great interest because of their cholinesterase inhibiting activity which causes them to be highly toxic nerve gases and also gives them medical activity (see Enzyme inhibitors). The most studied is the bis(l-methylethyl)ester of phosphorofluoridic acid also known as diisopropyl phosphorofluoridate [155-91 DFP (5), and as the ophthalmic ointment or solution Isoflurophate USP. It is used as a... 

The toxicity of a substance is its capacity to cause injury once inside the body. The main modes of entry into the body by chemicals in industry are inhalation, ingestion and absorption through the skin. Gases, vapours, mists, dusts, fumes and aerosols can be inhaled and they can also affect the skin, eyes and mucous membranes. Ingestion is rare although possible as a result of poor personal hygiene, subconscious hand-to-mouth contact, or accidents. The skin can be affected directly by contact with the chemicals, even when intact, but its permeability to certain substances also offers a route into the body. Chemicals accorded a skin notation in the list of Occupational Exposure Limits (see Table 5.12) are listed in Table 5.2. Exposure may also arise via skin lesions. 

Attention focused on events that cold release a quantity of flammable, explosive or to,xic vapors, hence, operations involving toxic liquefied gases such as ammonia and hydrogen fluoride, and flammables such as LNG and LPG. 

Partial enclosure An enclosure used for work with toxic dusts, gases, or vapors in which one or more of the sides may be open to the remainder of the work area. 

Reduction of cnviromncntal pollution requires lower energy use and new technology to decrease emission of gases such as sulfur dioxide and carbon dioxide, and to prevent toxic fluoride, heavy metal, and radioactive wastes from discharging into the environment. 

Wet and dry scrubbers Dry scrubbers are generally preferred today. Scrubbers can be used for the removal of both particulate matter and toxic sulfur gases (dry scrubber or spray dryer desulfurizers). 

Poisoning from toxic combustion products. In chemical fires, particularly those involving mixtures, an extremely complex mixture of gases and particulates, e.g. smoke may be produced. The composition depends upon the initial compounds involved, the temperatures attained and the oxygen supply, and is hence often unpredictable. Some gaseous compounds may derive from thermal breakdown, i.e. pyrolysis, of the chemicals rather than oxidation as illustrated in Tables 3.9 and 3.10. 

As a possible chemical process for distributed manufacture, the production of toxic feedstock gases is claimed [1,139]. Benson and Ponton were among the first... 

Metallic recuperators are practically leak-proof and so are also capable ofhandling toxic fuel gases. The ceramic recuperators leak to the extent of about 50% of the volume gases and air handled. 

STABREX is easier and simpler to use compared to any other oxidant available for industrial water treatment. The product is pumped directly from returnable transporters (PortaFeed Systems)17 with standard chemical feed equipment. Previously, the only practical ways to apply bromine were to oxidize bromide solutions on-site with chlorine in dual liquid feed systems, or with one of the solid organically-stabilized bromine products applied from sidestream erosion feeders. The former is cumbersome and complex, and the latter is prone to dusting and difficult to control. Other oxidants require complex handling and feed of toxic volatile gases, unstable liquids, multiple-component products, or reactive solids. Simplicity in use results in reduced risk to workers and to the environment. 

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