Unconsciousness

Intrusiveness. Workers are likely to alter their behavior, consciously or unconsciously, when they are observed. To the extent that a worker s exposure is related to the worker s actions, this change can distort the representativeness of the evaluation. Measurement methods which require the close presence of the person collecting the sample are more likely to influence the result than samples collected with unobtmsive devices worn by the worker. 

The toxic symptoms from inhalation of nickel carbonyl are beUeved to be caused by both nickel metal and carbon monoxide. In many acute cases the symptoms ate headache, di22iQess, nausea, vomiting, fever, and difficulty in breathing. If exposure is continued, unconsciousness follows with subsequent damage to vital organs and death. Iron pentacarbonyl produces symptoms similar to nickel carbonyl but is considered less toxic than nickel carbonyl. 

Trichloroethylene is acutely toxic, primarily because of its anesthetic effect on the central nervous system. Exposure to high vapor concentrations is likely to cause headache, vertigo, tremors, nausea and vomiting, fatigue, intoxication, unconsciousness, and even death. Because it is widely used, its physiological effects have been extensively studied. 

It is estimated that concentrations of 3000 ppm cause unconsciousness in less than 10 minutes (39). Anesthetic effects have been reported at concentrations of 400 ppm after 20-min exposure. Decrease in psychomotor performance at a trichloroethylene concentration of 110 ppm has been reported in one study (33), whereas other studies find no neurotoxic effects at concentrations of 200 ppm (40—43). 

Overexposure to tetrachloroethylene by inhalation affects the central nervous system and the Hver. Dizziness, headache, confusion, nausea, and eye and mucous tissue irritation occur during prolonged exposure to vapor concentrations of 200 ppm (15). These effects are intensified and include incoordination and dmnkenness at concentrations in excess of 600 ppm. At concentrations in excess of 1000 ppm the anesthetic and respiratory depression effects can cause unconsciousness and death. A single, brief exposure to concentrations above 6000 ppm can be immediately dangerous to life. Reversible changes to the Hver have been reported foUowing prolonged exposures to concentrations in excess of 200 ppm (16—22). Alcohol consumed before or after exposure may increase adverse effects. 

Ingestion. Ingestion, unless prompt first aid or medical treatment is given, is rapidly fatal 1 mg of cyanide per kilogram of body weight can be fatal. Immediate and repeated adininistration of emetics and regurgitation (if the victim is conscious), followed or accompanied by the first aid and medical treatments described below should be carried out. If the victim is unconscious, stomach lavage should be performed by a physician or trained personnel. 

A concentration of 35,000 ppm in air produces unconsciousness in 30—40 minutes. This concentration also constitutes a serious fire and explosion hazard, and should not be permitted to exist under any circumstance. Any person exposed to ethyl ether vapor of any appreciable concentration should be prompdy removed from the area. Recovery from exposure to sublethal concentrations is rapid and generally complete. Except in emergencies, and then only with appropriate protective equipment, no one should enter an area containing ether vapor until the concentration has been found safe by measurement with a combustible-gas indicator. 

Mental failure, nausea, vomiting, fainting, unconsciousness, ashen face, blueness of lips. 

ASPHYXIA The result of a diminished supply of oxygen to the blood and tissues and interference with the respiratory function. Simple anoxia may be caused by inert gases , e.g. nitrogen, and some flammable gases, e.g. methane. Toxic anoxia may be caused by certain substances, e.g. carbon monoxide and hydrogen cyanide, which interfere with the body s ability to transfer or utilize oxygen in the tissues. Rapid unconsciousness and death can occur in either case. 

Headache, vomiting, dizziness, disorientation, unconsciousness, death after a few minutes... 

Carbon monoxide is extremely toxic by inhalation since it reduces the oxygen-carrying capacity of the blood. In sufficient concentration it will result in unconsciousness and death. Typical reactions to carbon monoxide in air are summarized in Table 5.31. 

Palpitation after 30 min at rest or 10 min exertion Unconscious after 30 min at rest or 10 min exertion... 

From inhalation at pressures above atmospheric, used in tunnelling or diving, or from breathing apparatus or resuscitation equipment, if the pressure is too high or exposure is prolonged. This may cause symptoms from pain to dyspnoea, disorientation and unconsciousness it may be fatal. 

If the casualty is unconscious, place in the recovery position and watch to see if breathing stops... 

Toxicity. Breathing moderate amounts of methyl ethyl ketone (MEK) for short periods of time can cause adverse effects on the nervous system ranging from headaches, dizziness, nausea, and numbness in the fingers and toes to unconsciousness. Its vapors are irritating to the skin, eyes, nose, and throat and can damage the eyes. Repeated exposure to moderate to high amounts may cause liver and kidney effects. 

Narcosis Narcosis is a state of deep stupor or unconsciousness, produced by a chemical substance, such as a drug or anesthesia. Inhalation of certain chemicals can lead to narcosis. For example, diethyl ether and chloroform, two common organic solvents, were among the first examples of anesthesia known. Many other chemicals that you would not suspect can also cause narcosis. For example, even though nitrogen gas comprises 80% of the air we breathe and is considered chemically inert (unreactive) it can cause narcosis under certain conditions. Always work with adequate inhalation and avoid inhaling chemical fumes, mists, dusts etc. whenever possible. Use fume hoods and respirators as necessary. 

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