Halogenated hydrocarbon poisoning

If several days have elapsed before the body is discovered, there is a tendency to tiiink that analysis for volatile poisons would be futile. In fact it should be one of the first groups to be checked. The presence of alcohols, toluene, and halogenated hydrocarbons... 

STERICOL (1300-71-6) see xylenols. STIBINE (7803-52-3) SbHj Flammable, highly poisonous, and thermally unstable gas (Fire Rating 4). Reacts with moisture, forming explosive hydrogen. Elevated temperatures above 390°F/198°C can cause fire and explosion. Reacts violently or explosively with strong oxidizers, nitric acid (especially concentrated HNOj), halogenated hydrocarbons, ammonia, ozone. Forms heat-sensitive explosive mixtures with ammonia. Only if flow can be stopped on small fires, use dry chemical powder (such as Purple-K-Powder), foam, or COj extinguishers. If flow cannot be stopped, evacuate and let fire bum itself out. 

Muscle poisons. Affect the muscles, causing muscle weakness and loss of function. Some substances affect smooth (involuntary) muscle. Example barium salts. Some affect cardiac muscle, producing cardiac arrhythmias, angina, and muscle weakness. Examples nicotine, halogenated hydrocarbons, carbon monoxide, potassium salts, nitrates. Cardiovascular poisons can cause coronary artery disease and hypertension. Example carbon disulfide (80). 

The transitory poisoning by scavengers is explained by competitive adsorption of a halogen-containing species on catalyst sites that are needed for the oxidation of CO and hydrocarbons. In the case of EDB it is thermodynamically probable that HBr 33), or Br2 is the actual adsorbed species (66). The possible interactions of EDB and EDC with TEL and the resulting loss in noble metal surface area on the one hand, and catalyst activity on the other, are very complex (66). 

To overcome the problems of gas-sensor failure due to poisoning of the elements, several manufacturers have used specific filter devices in front of the elements. For example, filters to remove alkyl lead compounds from petrol vapour have included paradichlorobenzene and fibrous silica (3). However, the most commonly used material is based on active charcoal. Such filters (4) effectively absorb many common poisons and inhibitors including silicones, alkyl lead compounds and halogen-containing species. However, along with the absorption of potentially harmful vapours, carbon filters will also absorb hydrocarbons. This effect in practice limits the use of such filters to detectors for C3 and lower hydrocarbons. They cannot be employed in general flammable gas detectors. 

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