Toxicants, mixed

Accessory materials and equipment used to process and apply epoxy adhesives can also be hazardous. Solvents that are used either to dilute the epoxy adhesive or to clean equipment after use can be both dangerous and toxic. Mixing equipment can run at very fast speeds, and caution needs to be exercised when one is operating such equipment. Curing equipment often runs at high temperatures and can create a fire or explosion hazard. Electrical hazards are also associated with most equipment. 

In HPLC, a semiprep column might be operated at 25 mL/min, using up solvent and generating waste at a rate of up to 36 L/24-h day, or just under two 20-L containers of solvent in and two 20-L containers out as waste. Each week, the user needs to have available at least 10-14, 20-L containers of new solvent and must dispose of about 10-14 20-L containers of toxic, mixed waste for each chromatograph. Most jurisdictions limit the amount of solvent allowed in a lab at any given time as a fire safety issue. The limit is usually 50 L. A whole lot of barrel rolling occurs. 

Combustion Handbook, Volume I, 3rd ed., 2001. Combustion Handbook, Volume II, 3rd ed., 1995. Incineration of Hazardous, Toxic, Mixed Wastes, 1993. Practical Pointers, 1989. ... 

Compatibihty of acetone with other materials should be carefliUy considered, especially in disposal of wastes. It reacts with chlorinating substances to form toxic chloroketones, and potentially explosively with some peroxy compounds and a number of oxidizing mixtures. Mixed with chloroform, acetone will react violently in the presence of bases. Other incompatibilities ate Hsted in the Sax handbook (53). 

In the absence of air, TEE disproportionates violently to give carbon and carbon tetrafluoride the same amount of energy is generated as in black powder explosions. This type of decomposition is initiated thermally and equipment hot spots must be avoided. The flammability limits of TEE are 14—43% it bums when mixed with air and forms explosive mixtures with air and oxygen. It can be stored in steel cylinders under controlled conditions inhibited with a suitable stabilizer. The oxygen content of the vapor phase should not exceed 10 ppm. Although TEE is nontoxic, it may be contaminated by highly toxic fluorocarbon compounds. 

A toxic component of braken fern, perhaps either quercetin (105) or ptaquiloside, a glucoside (106), has a mixed history of carcinogenicity. It is sometimes impHcated in an increased incidence of bladder cancer in animals and esophageal cancer in humans. Multiple other dietary components seem to either promote or interfere with its action, and the significance of braken fern in human carcinogenesis remains unproven. 

Chloroprocaine hydrochloride [3858-89-7] is characterized by low potency, rapid onset, short duration of action, and low systemic toxicity. It is indicated for infiltration anesthesia at 1—2% and for extradural anesthesia at 2—3% when short surgical procedures are performed under regional anesthesia. Chloroprocaine may be mixed with long duration agents such as bupivacaine (22, R = n-Q [) to afford a more rapid onset and shorter duration of action than bupivacaine alone. 

Depending on the circumstances of exposure, any given material may produce more than one type of toxic effect. Therefore, when describing toxicity for a particular material, it is necessary to define whether the effect is local, systemic, or mixed the nature of the injury the organs and tissues affected and the conditions of exposure, including route of exposure, number of exposures, and magnitude of exposure. 

When iadustrial wastewaters are mixed with municipal wastes, as ia many urban systems, toxic and inhibitory materials are removed ia the pretreatment system where nutrient chemicals, eg, nitrogen and phosphoms, are added. 

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