Mishaps

Usually reactions are carried out without mishaps, but sometimes chemical reactions get out of control because of problems such as using the wrong raw material, using raw materials containing trace impurities, changed operating conditions, unanticipated time delays, equipment failure, or wrong materials of construction. 

Such mishaps can be worse if the chemistiy is not fuUy understood. A chemical plant can be inherently. safer if knowledge of the chemistiy of the process and the reactive chemicals systems involved is used in its design. 

Some tolled products can be reworked if they fail quality assurance tests. In these cases the production cost may go up, but the product is not a complete loss. However, other tolled products, some pharmaceuticals for example, could be completely ruined by similar processing mishaps. Losses in these cases can be quite extensive. Test runs and approved rework procedures for such products may help avoid these losses. 

Experimental chemistry is a very dangerous occupation and extreme care and adequate safety precautions should be taken at all times. Although we have stated the safety measures that have to be taken under specific entries these are by no means exhaustive and some may have been unknowingly or accidentally omitted. The experimenter without prior knowledge or experience must seek further safety advice on reagents and procedures from experts in the field before undertaking the purification of any material. We take no responsibility whatsoever if any mishaps occur when using any of the procedures described in this book. 

Check for plant integrity/flammable leaks periodically or continuously on-line, as appropriate Install appropriate fire/smoke detection, audible alarms Provide adequate fire suppression systems Deal with mishaps such as spillage immediately... 

Anytime hazardous materials are eneountered, the potential for a mishap to oeeur inereases. Should the hazardous materials be eonsidered waste produets, eomplianee issues beeome more important. Elazardous waste operations and work aetivities should be evaluated to determine if the operation should eomply with HAZWOPER or other regulatory guidelines. 

Adequate resources are fundamental to any project, but even more so to a well-functioning health and safety program. Many mishaps have been traced to improperly trained workers, lack of adequate tools and equipment, or requirements for personnel to work excessive hours or at unfamiliar jobs because of inadequate staffing or lack of adequate resources. The multidisciplinary team approach can help to identify required resources and can help balance, identify, and coordinate necessary assets. 

Human Error and Occupational Mishaps Transport Accidents... 

Occupational mishaps me usiwlly a function of three aspects of the work place the human element, task vtiriabies (i.e., the job itselO. nnd the environmental element. 

When e alualing human elements in relation to occupational mishaps, five factors are taken into consideration. 

Risk iuialysis of accidents serves a dual purpose. It estimates tlie probability tliat iui accident will occur and also assesses the severity of the consequences of an accident. Consequences may include dmnage to tlie surrounding enviromnent, financial loss, injury to life and/or deatli. This Part of the book (Part IV) is primarily concerned witli tlie metliods used to identify liazards and causes and consequences of accidents. Issues dealing witli healtli risks have been explored in die previous Part (III). Risk assessment of accidents provides an effective way to help ensure eidier diat a mishap will not occur or reduces the likelihood of an accident. The result of die risk assessment also allows concerned parties to take precautions to prevent an accident before it happens. 

Miss-f bung, /. discoloration, -geschick, n. misfortune mishap. 

Bridenstine JB, Dolezal JF (1994) Standardizing chemical peel solution formulations to avoid mishaps. Great fluctuations in actual concentrations of trichloroacetic acid. J Dermatol Surg Oncol 20 813-816... 

Deal with mishaps such as spillage immediately... 

The rate of product to be applied is the critical factor affecting all residue studies. The rate should be the highest recommended rate for that particular crop and should be applied at the limit of the GAP for the specific crop. The test item should ideally be pre-weighed in a laboratory prior to making the application. In most cases, this procedure results in easier accountability of test items, more accurate measurement of required doses, and more accurate application in the field since only the correct amount of water is required to be added by the field operator. This procedure also reduces the quantity of test item required and hence reduces the waste, which has to be disposed of. An additional spare sample, which is weighed at the same time in case of mishap with the original sample may be prepared. 

The importance of safety has been discussed in Chapter 4. At this point, it is necessary to look at each stage of the process to see what might go wrong and, if this happened, what might be done to prevent any mishap from occurring. 

Some plants can be operated essentially without any people. However, for safety purposes there usually are two employees per shift. Then if some mishap should occur to one man, the other can obtain help. This implies that a plant can be over-automated. The operators can become bored if they do not have some tasks to perform. If these are make-work tasks, the operators will rapidly determine this, and either the tasks will be ignored or the reports will be falsified. To keep these men alert, and sufficiently knowledgeable and involved so that they can respond quickly and properly when an emergency arises, it may be best not to automate the plant totally. 

If one has three or four completely accurate points, an adequate test of the linearity of the assumed concentration function could be made. However, one cannot be sure whether departures from linearity are the result of scatter of the data, of a slowly curving function, or of some combination of these circumstances. When one further recognizes that one or two points in a set of data may be in error as a result of an experimental mishap and that these points may deviate substantially from the line established by the rest of the data, one comes to the conclusion that it is desirable to have eight to ten data points per run. 

Thermally unstable at 22°C and explosive in the gas phase at pressures above 27-62 mbar [1], there is also an explosion hazard during distillation and trapping at -78°C [2], The crude (80%) material prepared by action of 3% fluorine in nitrogen on sodium trifluoroacetate [3] has, however, been used synthetically for 3 years without mishap [4]. 

Dining the preparation of 2-azidoethanol from a stirred mixture of 2-bromoethanol (14.6 mol) and sodium azide (15.4 mol) heated on a steam bath, a violent explosion occurred after 100 min. The preparation had been carried out previously without mishap. The need for care in handling azides of low MW is stressed [1], Later detailed studies showed that the most probable cause of the explosion was the extraordinarily high mechanical and thermal sensitivity of the compound, with initiation by vibration from the agitator [2],... 

During reflux of a mixture to produce malonoyl chloride, vivid sparks were seen in the flask, and the reaction was closed down without mishap. No explanation is apparent, but the diisopropyl ester structure appears likely to be susceptible to autoxidation on storage, and peroxides may possibly have been involved in the phenomenon. 

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