Danger agents

The best way to control exposure is to replace dangerous agents with safer ones. Today, highly toxic solvents, such as benzene, bromobenzenc, carbon tetrachloride, and chloroform are no longer extensively used. Benzene remains, however, an important chemical in the petrochemical industry, but the processes where it is used are clc)sed. 

Serious and fatal blood dyscrasias occur after short-term and prolonged therapy with chloramphenicol. Aplastic anemia, which later terminated in leukemia, has been reported. Chloramphenicol must not be used when less potentially dangerous agents are effective. It must not be used to treat trivial infections or infections other than indicated, or as prophylaxis for bacterial infections. 

If presumptive therapy is initiated, perform in vitro sensitivity tests concurrently, so that the drug may be discontinued if less potentially dangerous agents are indicated. Acute infections In acute infections caused by Salmonella typhi, chloramphenicol is a drug of choice. 

The most dangerous agents are the biological agents and the toxins. Protozoa, for example Cryptosporidium parvum, have contaminated a water supply system with serious consequences. In 1993, the supply of Milwaukee was contaminated, 100 people died, and over 400,000 became ill. Although this protozoan causes serious health effects in the very young, the very old, and the... 

How is one to regard an insect s ability to tolerate and sequester PAs Do species such as Utetheisa and Danaus have modified P-450 enzymes, or do they shield ingested PAs from exposure to these potentially dangerous agents Have they, in a sense, through biochemical one-upmanship, themselves succeeded in countering the plant s defenses ... 

Chlorine was quickly replaced by the Germans with diphosgene and phosgene (first used in December 1915). Phosgene, with its early upper respiratory irritant effects and late onset pulmonary oedema (see Chap. 6), proved to be one of the most dangerous agents of the war. 

Cytokines, eg, interferons, interleukins, tumor necrosis factor (TNF), and certain growth factors, could have antitumor activity directiy, or may modulate cellular mechanisms of antitumor activity (2). Cytokines may be used to influence the proliferation and differentiation of T-ceUs, B-ceUs, macrophage—monocyte, myeloid, or other hematopoietic cells. Alternatively, the induction of interferon release may represent an important approach for synthetic—medicinal chemistry, to search for effective antiinflammatory and antifibrotic agents. Inducers of interferon release may also be useful for lepromatous leprosy and chronic granulomatous disease. The potential cytokine and cytokine-related therapeutic approaches to treatment of disease are summarized in Table 4. A combination of cytokines is a feasible modaUty for treatment of immunologically related diseases however, there are dangers inherent in such an approach, as shown by the induction of lethal disserninated intravascular coagulation in mice adrninistered TNF-a and IFN-y. 

Methanol is stable under normal storage conditions. Methanol is not subject to hazardous polymerization reactions, but can react violendy with strong oxidizing agents. The greatest hazard involved in handling methanol is the danger of fire or explosion. The NFPA classifies methanol as a serious fire hazard. 

Most trialkylarsines are volatile Hquids with intensely disagreeable odors. They react readily with oxygen, and in some cases they ignite spontaneously when exposed to air. Triarylarsiaes are soHds that can usually be handled in air without danger of oxidation. They are, however, easily converted to triarylarsine oxides with suitable oxidi2ing agents (73). 

Potassium-sparing by diuretic agents, particularly spironolactone, enhances the effectiveness of other diuretics because the secondary hyperaldosteronism is blocked. This class of diuretics decreases magnesium excretion, eg, amiloride can decrease renal excretion of potassium up to 80%. The most important and dangerous adverse effect of all potassium-sparing diuretics is hyperkalemia, which can be potentially fatal the incidence is about 0.5% (50). Therefore, blood potassium concentrations should be monitored carehiUy. 

The isothiazole ring does not occur in nature. By far the most important synthetic isothiazole derivative is saccharin. This was the first non-carbohydrate sweetening agent to be discovered, as long ago as 1879. It is about 300 times as sweet as sucrose, and is still used in many countries as a non-nutritive sweetener. After it was found that administration of massive doses to rats caused bladder cancer, its use was banned in the New World, but the controversy continues as to whether there is any danger when it is used in small quantity. Saccharin is also used as an additive in electroplating processes (73AHC(15)233). 

IDLH means immediately dangerous to life and health. This is a concentration at which immediate action is required. The exac4 effect on an individual depends on the individuals physical condition and susceptibility to the toxic agent involved. It is the maximum airborne contamination concentration from which one could escape within 30 min without any escape-impairing symptoms or irreversible health effects (developed by NIOSH). 

Where there is a danger of contamination of a hydrocarbon polymer with such ions it is common practice to use a chelating agent which forms a complex with the metal. It is, however, important to stress that a chelating agent which effectively slows down oxidation initiated by one metal ion may have a prooxidant effect with another metal ion. Table 7.5 summarises some work by... 

Corrosivity Contamination factors (incompatibility), oxidizing or reducing agent, dangerous reactions ... 

Electrical plant, electrical installations Non-conductivity of extinguishing agent most important Dangerous Most suitable Most suitable No Yes" No No... 

A Shippers, shipper s agents including operator s staff acting as shippers, operator s staff preparing dangerous goods B Packers... 

Major hazard aspects of the transport of dangerous substances 1991 Recommendations for training users of non-agricultural pesticides Health surveillance under COSHH. Guidance for employers Anaesthetic agents. Controlling exposure under COSHH Risk assessments of notified new substances... 

---