Chemicals precautions

Safety glasses must be worn in the laboratory at all times. Other personal protection equipment should be worn as needed, especially appropriate safety gloves. Sodium fluoride is a deadly poison if ingested full chemical precautions should be observed. Material safety data sheets (MSDS) should be reviewed before beginning the experiment. 

Workup in the lab should use standard precautions for working with compounds of unknown biological properties. Caution should be taken not to expose oneself to the compounds in any way. Wear gloves when necessary, work in chemical fiime hoods, prevent contact of any compounds with the skin, do not ingest any of the sample, and do not smell the sample directly. If for some reason, the sample must be smelled (the author recommends that you don t), use normal chemical precautions, and waft the vapor towards your nose in order to minimize exposure. 

It stands to reason that if hazardous chemical precautions are going to function, the employee must read labels and follow the directions and information presented and know where the MSDSs are filed and refer to them if an unusual situation requires it. 

Some further details are the following. Film nonideality may be allowed for [192]. There may be a chemical activation barrier to the transfer step from monolayer to subsurface solution and hence also for monolayer formation by adsorption from solution [294-296]. Dissolving rates may be determined with the use of the radioactive labeling technique of Section III-6A, although precautions are necessary [297]. 

Other sources of hazard arise from the handling of such chemicals as concentrated acids, alkalis, metallic sodium and bromine, and in working with such extremely poisonous substances as sodium and potassium cyanides. The special precautions to be observed will be indicated, where necessary, in the experiments in which the substances are employed, and will also be supplied by the demonstrator. The exercise of obvious precautions and cautious handling will in most cases reduce the danger to almost negligible proportions. Thus, if concentrated sulphuric acid should be accidentally spilled, it should be immediately washed with a liberal quantity of water or of a solution of a mild alkali. 

In professional laboratories fume hoods are big metal boxes resting on counter tops and are connected by ducts to blower motors on the roof of the facility. The blower motor is constantly sucking the air from the hoods to the outside so that chemists will not be exposed to the vapors of chemicals they are working with inside the hood. The same precautions are taken by non-dead underground chemists. 

Although isotope-dilution analysis can be very accurate, a number of precautions need to be taken. Some of these are obvious ones that any analytical procedure demands. For example, analyte preparation for both spiked and unspiked sample must be as nearly identical as possible the spike also must be intimately mixed with the sample before analysis so there is no differential effect on the subsequent isotope ration measurements. The last requirement sometimes requires special chemical treatment to ensure that the spike element and the sample element are in the same chemical state before analysis. However, once procedures have been set in place, the highly sensitive isotope-dilution analysis gives excellent precision and accuracy for the estimation of several elements at the same time or just one element. 

Normal precautions for chemicals of mild toxicity are appHcable to the safe handling and storage of commercial tetrahydrofurfuryl alcohol. Discoloration in storage rarely occurs if the proper precautions are observed prevention of exposure to air wiH prevent autoxidation. The Hst price of tetrahydrofurfuryl alcohol (1997) is 1.15/lb. 

Xandiene dyes have not exhibited health or safety properties warranting special precautions however, standard chemical labeling instmctions are required. Toxicological properties of important dyes are Hsted in Table 2 (12). 

To an experienced operator trained in the handling of industrial chemicals, the dimers present Httle cause for concern in handling or storage. The finished polymer coating presents even less of a health problem contact with the reactive monomer is unlikely. In the ancillary operations, such as cleaning or adhesion promotion, the operator must observe suitable precautions. Before using the process chemicals, operators must read and understand the current Material Safety Data Sheets, which are available from the manufacturers. 

Chemical safety data sheets for individual compounds should be consulted for detailed information. Precautions for the higher aldehydes are essentially those for most other reactive organic compounds, and should include adequate ventilation in areas where high exposures are expected fire and explosion precautions and proper instmction of employees in use of respiratory, eye, and skin protection. 

Workers in the metals treatment industry are exposed to fumes, dusts, and mists containing metals and metal compounds, as well as to various chemicals from sources such as grinding wheels and lubricants. Exposure can be by inhalation, ingestion, or skin contact. Historically, metal toxicology was concerned with overt effects such as abdominal coHc from lead toxicity. Because of the occupational health and safety standards of the 1990s such effects are rare. Subtie, chronic, or long-term effects of metals treatment exposure are under study. An index to safety precautions for various metal treatment processes is available (6). As additional information is gained, standards are adjusted. 

Health and Safety Factors. Terephthahc acid has a low order of toxicity. Inhalation by rats for 6 h/d, 5 d/wk for 4 wk produced no fatahties at a dust exposure level of 25 mg/m. The mean acute oral toxicity for rats is over 18 g/kg (86), and for mice over 6 g/kg (87). When terephthahc acid was fed as 3% of the diet to rats, urinary calcuh formed in 90 d, some of which led to cancer. High doses of terephthahc acid lead to formation of calcium terephthalate at levels exceeding its solubihty in urine. This insoluble material leads to the calcuh and provides a threshold below which cancer is not observed (88). Normal precautions used in handling industrial chemicals should be observed with terephthahc acid. If ventilation is inadequate, a toxic-dust respirator should be used to avoid prolonged exposure. 

Health and Safety Factors. Isophthahc acid has a low order of toxicity. Inhalation by rats for 4 h at 11.4 g/m showed no toxicity. The LD -level for rats is high at 10.4 g/kg (96). As with terephthahc acid, isophthahc acid was found to form urinary tract calcuh in rats in 90 d when it constituted 3% of their diet. This led to some cancer owing to the presence of the calcuh. Some mild eye irritation is possible, so eye protection should be worn. Otherwise, normal precautions used in handling industrial chemicals should be observed with isophthahc acid. 

Chemical fertiliser is the predominant market for langbeinite. Comparatively small but increasing amounts of langbeinite are used by the animal feed ingredient industry (see Feeds and feed additives). Producers who supply this market must take special precautions to be sure that any langbeinite intended as an animal feed ingredient meets all USDA specifications for toxic heavy metals and other impurities. 

Potassium compounds commonly used in ferti1i2ers, eg, KCl and K SO, are not considered to be ha2ardous substances. Detailed information concerning health and safety precautions recommended for a specific, industrially produced potassium chemical can be obtained by contacting a manufacturer direcdy. Principal potassium chemical producers are Hsted in buyers guides pubHshed aimually by chemical trade maga2ines (52). 

The need for skill and experience on the part of sample designers and persoimel cannot be overemphasized in chemical plant sampling. Safety precautions are of the utmost importance. Necessary steps must be taken to document the hazards involved in an operation and to ensure that the staff are weU-trained, informed, protected, and capable. Except for bulk powder sampling, most chemical plant sampling is hazardous and difficult and must be designed with care. The following discussions are based on the assumptions that most of these decisions have been made and a satisfactory sampling procedure has been planned. 

The Shoe grouting system is considered nonhazardous and nonpolluting. Sodium silicate is essentially nontoxic. Formamide is toxic and corrosive, but does not present a serious hazard if normal safety precautions are followed. Shoe chemical grout materials are two to five times more expensive than Portland cement, depending on the sodium silicate to formamide concentration ratios. Installed costs are generally more similar to those for cement grouts. 

Shipment and Storage. Sulfur dichloride, if kept dry, is noncorrosive at ambient temperatures, thus carbon steel and Hon can be used Hi the constmction of tanks, piping, and dmms. However, when water or humidity is present, materials resistant to hydrochloric acid must be used, eg, glass-lined pipe. Teflon, titanium, HasteUoy C, or possibly a chemically resistant, glass-reiaforced polyester. Threaded pipe joHits should be assembled with Teflon tape. Hoses should be constmcted with a Teflon inner lining with the outer tube constmcted of Neoprene or braided 316 stainless steel protected by an adequate thickness of Teflon. Sulfur dichloride should be stored away from heat and away from dHect rays of the sum. Toluene and sulfur dichloride react exothermically when catalyzed by Hon or ferric chloride. Safety precautions should be foUowed when such a mixture is present (165). 

Thioglycohc acid is stored ia reiaforced polyethylene or polypropylene tanks or contaiaers. It is advisable to keep thioglycohc acid at low (<10° C) temperature to slow down self-esterification. The same care must be taken with dmms or tank tmcks. Dmms are made of polyethylene or polyethylene-liaed steel. For transport, thioglycohc acid is classified as a corrosive and toxic hquid. The handling of thioglycohc acid requires the usual precautions observed for strong acid and corrosive chemicals. 

Toxicology. The toxicity of ethyl ether is low and its greatest hazards in industry are fire and explosion. The vapor is absorbed almost instandy from the lungs and very prompdy from the intestinal tract. It undergoes no chemical change in the body. Prevention and control of health hazards associated with the handling of ethyl ether depend primarily on prevention of exposure to toxic atmospheric concentrations and scmpulous precautions to prevent explosion and fire. 

In contrast to other cryogenic fluids, liquid oxygen is slightly magnetic. It is also chemically reactive, particularly with hydrocarbon materials. Oxygen thus presents a safety problem and requires extra precautions in handling. 

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