Respiratory poisons

Atropiae (41), isolated from the deadly nightshade Airopa belladonna L.) is the racemic form, as isolated, of (—)-hyoscyamine [which is not isolated, of course, from the same plant but is typically found ia solanaceous plants such as henbane (HyosQiamus mgerl. )]. Atropiae is used to dilate the pupil of the eye ia ocular inflammations and is available both as a parasympatholytic agent for relaxation of the intestinal tract and to suppress secretions of the saUvary, gastric, and respiratory tracts. In conjunction with other agents it is used as part of an antidote mixture for organophosphorus poisons (see Chemicals in war). 

Both sodium fluoride and sodium bifluoride are poisonous if taken internally. Dust inhalation and skin or eye contact may cause irritation of the skin, eyes, or respiratory tract, and should be avoided by the use of proper protective equipment (1). 

Propylene oxide is a primary irritant, a mild protoplasmic poison, and a mild depressant of the central nervous system. Skin contact, even in dilute solution (1%), may cause irritation to the eyes, respiratory tract, and lungs. Propylene oxide is a suspected carcinogen in animals. The LC q (lowest lethal concentration by inhalation in tats) is 4000 mg/kg body weight. The LD q (oral) is 930 mg/kg. The LD q (dermal) is 1500 mg/kg. The TWA (8-h exposure) is 100 ppm and the STEP (15-min exposure) is 150 ppm. 

Health and Safety Factors. Carbonyl sulfide is dangerously poisonous, more so because it is practically odorless when pure. It is lethal to rats at 2900 ppm. Studies show an LD q (rat, ip) of 22.5 mg/kg. The mechanism of toxic action appears to iavolve breakdowa to hydrogea sulfide (36). It acts principally on the central nervous system with death resulting mainly from respiratory paralysis. Little is known regarding the health effects of subacute or chronic exposure to carbonyl sulfide a 400-p.g/m max level has been suggested until more data are available (37). Carbon oxysulfide has a reported inhalation toxicity in mice LD q (mouse) = 2900 ppm (37). 

Health nd Safety Factors. Thionyl chloride is a reactive acid chloride which can cause severe bums to the skin and eyes and acute respiratory tract injury upon vapor inhalation. The hydrolysis products, ie, hydrogen chloride and sulfur dioxide, are beheved to be the primary irritants. Depending on the extent of inhalation exposure, symptoms can range from coughing to pulmonary edema (182). The LC q (rat, inhalation) is 500 ppm (1 h), the DOT label is Corrosive, Poison, and the OSHA PEL is 1 ppm (183). The safety aspects of lithium batteries (qv) containing thionyl chloride have been reviewed (184,185). 

Health and Safety Factors. Sulfuryl chloride is both corrosive to the skin and toxic upon inhalation. The TLV suggested by the manufacturer is 1 ppm. The vapors irritate the eyes and upper respiratory tract, causing prompt symptoms ranging from coughing to extreme bronchial irritation and pulmonary edema. The DOT label is Corrosive, Poison. 

Acute benzene poisoning results in CNS depression and is characterized by an initial euphoria followed by staggered gait, stupor, coma, and convulsions. Exposure to approximately 4000 ppm benzene results in complete loss of consciousness. Insomnia, agitation, headache, nausea, and drowsiness may persist for weeks after exposure (126). Continued inhalation of benzene to the point of euphoria has caused irreversible encephalopathy with tremulousness, emotional lability, and diffuse cerebral atrophy (125). In deaths arising from acute exposure, respiratory tract infection, hypo- and hyperplasia of sternal bone marrow, congested kidneys, and cerebral edema have been found at autopsy. 

Toxicity of 2-Ghloroethanol. Ethylene chlorohydrin is an irritant and is toxic to the Hver, kidneys, and central nervous system. In addition, it is rapidly absorbed through the skin (73). The vapor is not sufficiently irritating to the eyes and respiratory mucous membranes to prevent serious systemic poisoning. Contact of the Hquid in the eyes of rabbits causes moderately severe injury, but in humans corneal bums have been known to heal within 48 hours. Several human fataUties have resulted from inhalation, dermal contact, or ingestion. One fatahty was caused by exposure to an estimated 300 ppm in air for 2.25 hours. In another fatal case, autopsy revealed pulmonary edema and damage to the Hver, kidneys, and brain (73). 

Hydrogen sulfide gas Hydrogen sulfide is a gas with a rotten egg odor. This gas is produced under anaerobic conditions. Hydrogen sulfide is particularly dangerous because it dulls your sense of smell so that you don t notice it after you have been around it for a while and because the odor is not noticeable in high concentrations. The gas is very poisonous to your respiratory system, explosive, flammable, and colorless. 

PuAEMACoLOGiCAL AcTiox. Curare is stated to be almost inert when taken by mouth, owing to poor absorption by intestinal mucous membrane and the rapidity of elimination. Injected hypodermically it is a rapid and potent poison, paralysing the motor nerve-endings in striped muscle, so that voluntary movements cease and death occurs from respiratory failure. 

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