Hazard physiological effects

Asphyxiation and Toxicity Hazards An asphyxiant is a chemical (either a gas or a vapor) that can cause death or unconsciousness by suffocation (BP, Hazards of Nitrogen and Catalyst Handling, 2003). A simple asphyxiant is a chemical, such as N2, He, or Ar, whose effects are caused by the displacement of 02 in air, reducing the 02 concentration below its normal value of approximately 21 vol %. The physiological effects of oxygen concentration reduction by simple asphyxiants are illustrated in Table 23-18 (BP, Hazards of Nitrogen and Catalyst Handling, 2003). 

Aside from the explosive hazard of A-nitrosamides, it also has been observed that many A-nitroso compounds have a serious physiological effect on mucous membranes and on the skin. Apparently, this corrosive action is not observed in the case of A,A -dinitroso-A,A -dimethyloxalamide [37a, b]. Even so, considering that some A-nitroso compounds are reputed to be carcinogenic, due care should be exercised in the handling of all nitroso compounds. 

Questions are sometimes raised about the potential harmful effects of ultrasound produced by laboratory-scale devices. Available data indicates that airborne ultrasonic fields do not appear to be hazardous to humans. There are, in fact, no known physiological effects from airborne ultrasound. Ultrasonic sickness appears to be largely psychosomatic. 

The relationship between the physiological effect of phosgene exposure and the corresponding hazard category has been assessed [ICI59] from extrapolation of information... 

Of the many rentes of toxic-material entry into humans, inhalation is the most likely to occur and is the rente specified in cnrrent legislation. Toxicity data have been developed for most of the important indnstrial chemicals [19] and form the basis for threshold or allowable concentrations to which persons cam be exposed with no significant physiological effect. Evaluation of toxicity hazards is then based on the duration of exposures to concentrations above these threshold levels. The concentrations of toxic materials in air are primarily functions of vapor pressure and temperature (for toxic liquids) the rate of gas, vapor, mist, or dust release or generation and distance from the source. 

The saltwater aquatic life protection criterion of 4.5 tLg Cd/L seems adequate to prevent death, but will not prevent potentially deleterious physiological effects, including dismpted respiration in crustaceans and teleosts. Incidentally, at 5.0 ttg Cd/L, the lowest concentration critically examined, oysters biomagnify ambient levels to concentrations hazardous to human consumers and possibly other animal consumers. The maximum allowable concentration (MAC) in saltwater during a 24-h period was recommended as 59.0p,g/L (Table 5.2). However, death of various species of marine crustaceans was reported at 60.0 p,g Cd/L after exposure for 6 weeks and at 14.8-19.5 ttg/L after 23-27 days. Furthermore, a MAC of... 

The preparation of potassium azide from aqueous potassium hydroxide and hydrazoic acid has been described earlier. 1 The preparation of hydrazoic acid is always hazardous because of its explosive nature and its unpleasant physiological effects. Consequently, an alternative procedure based on the initial reaction of hydrazine with nitrous acid is described here. 

In recent years, there has been increasing emphasis placed on the health effects of chemical exposures. However, as has been frequently noted, health effects are much more difficult to quantitatively characterize than most physical safety parameters. It is straightforward to define with reasonable accuracy a number of physical hazards, such as the upper and lower explosive limits of the vapors of a flammable material. However, the exposure levels (see Figure 4.16, taken from the Federal Register Vol. 53, No. 109, June 7, 1988, p. 21342) which will cause a given physiological effect in humans are not nearly as precise, especially if the effect of interest is delayed or is due to prolonged exposure to low levels of a toxic material. 

In a moment of humor people say, It s not the fall that is so bad, it s the sudden stop when you hit the ground. One must understand the physics of falls in order to understand the potential severity. Understanding physics and some physiology will also help one understand design features and how to reduce hazards through effective controls. Three important aspects of falls are (a) the motion and height of a falling body (b) the impact as a fall stops and (c) the ability to withstand impact. 

Smoke is produced by burning hydrocarbons and solids in considerable quantities, (particularly under conditions of incomplete combustion). It is also produced in large quantities by burning electrical and electronic equipment. Smoke consists of finely divided particulate matter and suspended liquid droplets (aerosols) and can contain toxic byproducts of combustion. Smoke creates a serious hazard to personnel due to its physiological effects and the reduction of visibility (most of the deaths on the Piper Alpha platform were of men in their living quarters who were overcome by smoke). 

Speciation is of great concern, as the chemical form of the pollutant influences its mobility in the environment, bioavailability, physiological effects and properties, and consequently its toxicity and level of health hazard. 

Minot, A.S., 1938. The physiological effects of small amounts of lead an evaluation of the lead hazard of the average individual. Physiol. Rev. 18, 554—574. 

In both its liquid and gaseous form, chlorine is neither flammable nor explosive. It currently is classified as a poison or toxic gas, class 2.3, which requires a subsidiary corrosive label. In Canada, it is classified as a corrosive gas, class 2.3. Its principal hazard arises from inhalation. The Chlorine Institute s Chlorine Manual describes chlorine s physiological effects, chemical characteristics, and physical properties. It also includes information on employee training for proper handling and protection when using chlorine [11]. Additional information on chlorine, including exposure limits, can be found in the monograph in Part II. 

Users can take the role of a mine worker or supervisor, in which egress from the mine might be the primary concern, or they can take the role of a rescue team member, in which the objective is to travel safely into the mine to rescue trapped workers. If atmospheric conditions start to deteriorate, the likely physiological effects can be fed back to the user to simulate differing levels of stress. The monitoring of hazardous situations and reaction to those hazards can be logged for later assessment. 

Methane liberation in the absence of effective ventilation can present serious hazards to miners. In addition to being an explosive gas, an accumulation of methane in high concentrations can result in a mine atmosphere that is deficient in oxygen. Atmospheres with oxygen concentrations below 19.5 percent can have adverse physiological effects, and atmo heres with less than 16 percent oxygen can become life... 

CAUTION Carbodiimides must be handled with extreme care since free amino groups in the tissue of the operator may readily be acylated. This may cause physiological effects which are potentially hazardous. 

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