Lethal substance

Subsection B This subsection contains rules pertaining to the methods of fabrication of pressure vessels. Part UW is applicable to welded vessels. Service restric tions are defined. Lethal service is for lethal substances, which are defined as poisonous gases or liquids of such a nature that a very small amount of the gas or the vapor of the liquid mixed or unmixed with air is dangerous to life when inhaled. It is stated that it is the user s responsibility to advise the designer or manufacturer if the service is lethal. All vessels in lethal service shall have all butt-welded joints fully radiographed, and when practical, joints shall be butt-welded. All vessels fabricated of carbon or low-aUoy steel shall be postweld-heat-treated. 

Although my own work at Edgewood was primarily dedicated to the evaluation of potenhal incapacitating agents, this book includes a discussion of nerve agents - the lethal substances that cause the greatest concern. It closes with a personal assessment of the current threat and a critique both of the facts released to the public, and the limitations of our government s information policies. 

Batrachotoxin A (III), just one of many steroidal alkaloids, is one of the most lethal substances known (LD50 = 2/xg/kg subcutaneously in mice). It is found in the skin secretions of the brightly colored tropical frog Phyllobates aurotaenia and is used by Colombian Indians to prepare poison darts. 

Botulinum toxin is produced by the bacterium Clostridium botulinum. It is among the most lethal substances known, and it has been estimated that 1-2 ounces of the pure toxin could kill the entire population of the United States. Poisoning of man and animals occurs when food containing the toxin is ingested. The most common source is improperly prepared canned fruits and vegetables or fish products. Although only... 

The response time of a chemical sensor should be appropriate for the application for which it is intended. For example, if the sensor is used to monitor acutely toxic (lethal) substances in the workplace, the response time should be faster than the biological/ toxicological re.sponse — perhaps only a few seconds. On the other hand, some applications, such as monitoring the spread of a chemical waste plume underground, have characteristic time scales of days to years, permitting utilization of sensors that respond more slowly. 

The duration of muscle paralysis following intoxication by BoNT/A exceeds that resulting from exposure to other BoNT serotypes (Keller et ah, 1999 Robinson and Nahata, 2003 Femandez-Salas et ah, 2004). The remarkable persistence of BoNT/A action has led to its widespread use in the treatment of disorders of muscle tone and movement (Jankovic and Brin, 1997). Although a long duration is desirable in clinical use, the prolonged action of BoNT/A would also make intoxication by this serotype difficult to treat, particularly if used as a bioweapon (Franz, 1997). The duration of intoxication by BoNT/E is relatively brief (several weeks), whereas BoNT/B is of intermediate duration (Keller et ah, 1999 Blanes-Mira et ah, 2004). The basis for the differences in serotype persistence is currently unknown. In any case, a bioterrorist attack, involving the most lethal substance known to humankind, would overwhelm the limited resources (i.e. mechanical ventilators) available to treat botulism patients. 

The vessels are not to be used to contain lethal substances, either liquid or gas. 

The BPV Code should be consulted to determine the allowed joint types for a particular vessel. Any pressure vessel containing lethal substances will require full radiographic testing of all butt welds. 

Ample evidence has been presented (15) to show that ozone in acute exposures is a highly toxic and lethal substance. The LDqq values for three rodent species are given in Table I. The LD q value is the dose of a substance that will on the average kill 50% of a significant number of animals exposed under specified conditions. Several experimentally simple and statistically sound methods of obtaining LD q values are available the one used in this work is that of Weil (19). The susceptibility or natural tolerance varies considerably with the species, the hamster being the least susceptible of the species tested. Although insufficient numbers of other species have been exposed to ozone to determine accurate LD q values, the dog would appear to resemble the ham-... 

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