Danger levels

Low molecular weight ether hydroperoxides are similarly dangerous and therefore ethers should be tested for peroxides and any peroxidic products removed from them before ethers are distilled or evaporated to dryness. Many ethers autoxidize so readily that peroxidic compounds form at dangerous levels when stored in containers that are not airtight (133). Used ether containers should be handled cautiously and if they are found to contain hazardous soHd ether peroxides, bomb-squad assisted disposal may be required (134). ZeoHtes have been used for removal of peroxide impurities from ethers (135). 

This can be limited by using a non-linear resistance called Metrosil across the relay, as shown in Figure 15.27. If voltage reaches a dangerous level, this resistance will provide a low-resistance parallel path to the current and limit the voltage across the relay to about I kV. The current / through the non-linear resistance is given by... 

V Z./C is the surge impedance, Z, L and C the circuit constants of the interrupting circuit, as discussed in (Section 17.6.4). C represents the dielectric capacitance between the parting contacts of the interrupter. must be prevented, as far as practicable, from reaching dangerous levels with the use of surge arresters. 

Most hydrocarbon gases are more soluble in cold oil than in hot oil and may lower the viscosity to a dangerous level. The problems of thrust-bearing failures during startup due to low-viscosity oil can be eliminated by equipping the reservoir with oil heaters to raise the oil to the normal operating temperatures before starting the machine. 

Heat stroke A serious acute condition caused by the elevation of the body temperature above the danger level. Symptoms can include redness of the face, reduced sweating, erratic behavior, confusion, dizziness, collapse, or unconsciousness. 

Clean up in such a way tliat the hazardous material is removed and does not produce a future danger. It may be necessary to pump out a hazardous liquid or to remove contaminated soil, etc. Decontamination procedures may be necessaiy. See EPA s Standard Operating Safety Guides for instructions for decontamination required following exposure to different danger levels of liazmds... 

In the event of an earth fault the difference in potential between any point which may be touched and the ground (touch potential) should not reach dangerous levels. 

The inherent mechanism that prevents the height of fever from reaching a potentially dangerous level. It is mediated by substances liberated both systemically and within the brain during fever that counter the formation or action of endogenous pyrogens, or inhibit the activity of neural circuits that modulate febrigenesis. 

Table 2.3 shows how dirty the Volga is. This is the river most contaminated by stable OCPs in Russia. Pesticides are present almost constantly in the water, bottom sediment, and hydro organisms of the downstream Volga and its deltas, and pesticide content sometimes exceeds MPC by a factor of thousands [1]. In Lake Baikal, the largest fresh water reservoir in the world, DDT content has also reached dangerous levels. According to 1988 data, 254... 

EPA. 1998b. Lead identification of dangerous levels of lead notice of proposed rulemaking. U.S. Environmental Protection Agency. Federal Register. 63 FR 30302. June 3, 1998. 

M272 Water Testing Kit A lightweight portable kit used to detect and identify dangerous levels of common chemical warfare agents in raw and treated water in about seven minutes. It is a test water sampler and is not a continuous monitor. Each kit includes twenty-five tests for each agent. 

Shellfish accumulate dangerous levels of PSP only under certain conditions. Typically, this occurs when the microorganisms undergo periods of very rapid growth, resulting from the simultaneous occurrence of several favorable environmental conditions. This growth, or bloom, frequently imparts a red color to the affected area of the ocean, and is referred to as a red tide. Shellfish growing in a red tide area can accumulate lethal amounts of PSP. 

One aspect of exercise that increases the risk of heatstroke is that the loss of heat by sweating requires a proportion of the cardiac output to be directed away from muscle to the skin. In this way, heat is lost from the blood as it circulates close to the skin. However, even in severe hyperthermia, the blood supply delivering fuel and oxygen to the muscles takes preference over that to the skin. In this way, symptoms of hyperthermia are overriden and physical activity is maintained so that the core temperature can rapidly increase to dangerous levels. (Neilsen et al. 1990). 

Two accidents of vastly differing severity have occurred at nuclear power plants. On 28 March 1979, an accident occurred in the nuclear power plant at Three Mile Island, Pennsylvania, USA. The radiation was contained and the small amount released had negligible effects on the health of individuals at the plant. On 26 April 1986 an accident occurred in the nuclear power plant 10 miles from the city of Chernobyl, then part of the Soviet Union. The chain reaction in the radioactive core of one of the four reactors became uncontrolled. Steam pressure rose to dangerous levels there were several explosions and a subsequent fire took several hours to extinguish. Large amounts of radioactive material were scattered over a wide area and into the atmosphere (later descending in a dilute form in rain all over the world). 

Homes with cracked concrete slabs or dirt basements are at risk for radon contamination. Radon is generated just under the surface of the Earth and can seep through the floors and walls. If the ventilation is poor in the basement, the gas can accumulate to a dangerous level. Inexpensive kits that measure the levels of radon in homes and businesses are available commercially. 

Nitrogen trifluoride provides no odorwarning properties at potentially dangerous levels. 

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