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Who knew?
Who knew? The Last Word
A
ny recent reader of our journal understands CHAS’s concern about a lack of sufficient lab safety training in our undergraduate and graduate chemistry programs. And yet, a student’s attitude toward safety and the presence or absence of a strong safety culture may be as significant as how many facts or principles of lab safety are discussed and demonstrated consistently in chemistry classes. Chemistry courses are full of facts. Nonmajors often employ a strategy of simply memorizing as many of the presented facts as possible and hope that exams will ask for a straightforward recounting of those facts. Hopefully, chemistry majors see the patterns in these facts and can use the pattern to anticipate facts that have not been explicitly discussed. But there are some important facts that seem to fall through the cracks in our education of chemists. Although important to the science of chemistry, especially in practical applications, these missing facts also have importance in lab safety. Who teaches chemistry undergraduates about scale-up issues? When and how do they learn that increasing the size of a reaction by a factor of ten or twenty can create problems that were not observed in the reactions described in the lab textbook? Two well-studied incidents in California and Texas laboratories involved problems arising because adverse scale-up consequences were not anticipated. Chemical engineers learn about these issues in school, but chemists usually do not. Looking at chemistry lab experiments today compared with lab experiments of past generations, one might reasonably conclude that the problem of hazardous chemicals can be solved simply by replacing the hazardous chemicals with non-hazardous ones. But where a safety professional might see a hazardous material, the synthetic chemist recognizes a reactive compound. Another important lesson that rarely is mentioned in chemistry classes is the relationship between the hazard of a specific chemical and the presence or absence of an unpleasant odor. There is no such relationship. There are non-hazardous chemicals with obnoxious odors and hazardous chemicals that have no odor (hydrogen cyanide, carbon monoxide). The presence or absence of odor is not indicative of the hazardous nature of a material.
1871-5532/$36.00 http://dx.doi.org/10.1016/j.jchas.2013.02.001
It would be nice if we could look at the chemical formula or structure of a molecule and accurately predict the hazards of that material. Why is benzene much more hazardous than toluene which just has an extra methyl group? Why is ethanol such a pleasant beverage (in moderation, of course) when a drink of methanol, which has one less methylene group, will make one quite ill? In most cases, we know a material is hazardous because we have witnessed its effect on people or the environment. How do chemists learn how to think about and work with mixtures of compounds? What might one anticipate about the hazards of hydrogen chloride in diethylether? How about n-butyllithium in hexane? A recent list of hazardous materials included ethanol as a reproductive hazard. In response to a followup inquiry, there was a Material Safety Data Sheet for ethanol that described the material as a reproductive toxin. But the specific ethanol product described by that MSDS was for ethanol denatured with 1–5% toluene. Anhydrous ethanol is not described as being a reproductive toxin. The toluene was the culprit in this case. And finally, how do chemistry students learn about lab waste disposal? Everything seems to get poured into the same container until the container gets full, then emptied and the cycle repeats. Would there be a beneficial value in explaining how waste streams are segregated and that each waste stream has one or more appropriate disposal routes? We can burn hydrocarbon wastes for the energy content, but adding some halogenated hydrocarbons to the container changes the classification of the waste. Where do the wastes go? How are they treated or recycled? Are any wastes buried in some sort of hazardous landfill somewhere? If students knew some of the story about lab waste disposal, they would appreciate efforts to make chemical processes greener. So where do tomorrow’s chemists learn about these various topics of useful information? Well, they learn some of it when they work with us or with their chemical safety professionals in their own organizations. Let’s look for opportunities to educate newer chemists about hazardous chemicals and the implications of working with them in our research. Let’s teach them to be careful out there.
ß Division of Chemical Health and Safety of the American Chemical Society Elsevier Inc. All rights reserved.
53
A
ny recent reader of our journal understands CHAS’s concern about a lack of sufficient lab safety training in our undergraduate and graduate chemistry programs. And yet, a student’s attitude toward safety and the presence or absence of a strong safety culture may be as significant as how many facts or principles of lab safety are discussed and demonstrated consistently in chemistry classes. Chemistry courses are full of facts. Nonmajors often employ a strategy of simply memorizing as many of the presented facts as possible and hope that exams will ask for a straightforward recounting of those facts. Hopefully, chemistry majors see the patterns in these facts and can use the pattern to anticipate facts that have not been explicitly discussed. But there are some important facts that seem to fall through the cracks in our education of chemists. Although important to the science of chemistry, especially in practical applications, these missing facts also have importance in lab safety. Who teaches chemistry undergraduates about scale-up issues? When and how do they learn that increasing the size of a reaction by a factor of ten or twenty can create problems that were not observed in the reactions described in the lab textbook? Two well-studied incidents in California and Texas laboratories involved problems arising because adverse scale-up consequences were not anticipated. Chemical engineers learn about these issues in school, but chemists usually do not. Looking at chemistry lab experiments today compared with lab experiments of past generations, one might reasonably conclude that the problem of hazardous chemicals can be solved simply by replacing the hazardous chemicals with non-hazardous ones. But where a safety professional might see a hazardous material, the synthetic chemist recognizes a reactive compound. Another important lesson that rarely is mentioned in chemistry classes is the relationship between the hazard of a specific chemical and the presence or absence of an unpleasant odor. There is no such relationship. There are non-hazardous chemicals with obnoxious odors and hazardous chemicals that have no odor (hydrogen cyanide, carbon monoxide). The presence or absence of odor is not indicative of the hazardous nature of a material.
1871-5532/$36.00 http://dx.doi.org/10.1016/j.jchas.2013.02.001
It would be nice if we could look at the chemical formula or structure of a molecule and accurately predict the hazards of that material. Why is benzene much more hazardous than toluene which just has an extra methyl group? Why is ethanol such a pleasant beverage (in moderation, of course) when a drink of methanol, which has one less methylene group, will make one quite ill? In most cases, we know a material is hazardous because we have witnessed its effect on people or the environment. How do chemists learn how to think about and work with mixtures of compounds? What might one anticipate about the hazards of hydrogen chloride in diethylether? How about n-butyllithium in hexane? A recent list of hazardous materials included ethanol as a reproductive hazard. In response to a followup inquiry, there was a Material Safety Data Sheet for ethanol that described the material as a reproductive toxin. But the specific ethanol product described by that MSDS was for ethanol denatured with 1–5% toluene. Anhydrous ethanol is not described as being a reproductive toxin. The toluene was the culprit in this case. And finally, how do chemistry students learn about lab waste disposal? Everything seems to get poured into the same container until the container gets full, then emptied and the cycle repeats. Would there be a beneficial value in explaining how waste streams are segregated and that each waste stream has one or more appropriate disposal routes? We can burn hydrocarbon wastes for the energy content, but adding some halogenated hydrocarbons to the container changes the classification of the waste. Where do the wastes go? How are they treated or recycled? Are any wastes buried in some sort of hazardous landfill somewhere? If students knew some of the story about lab waste disposal, they would appreciate efforts to make chemical processes greener. So where do tomorrow’s chemists learn about these various topics of useful information? Well, they learn some of it when they work with us or with their chemical safety professionals in their own organizations. Let’s look for opportunities to educate newer chemists about hazardous chemicals and the implications of working with them in our research. Let’s teach them to be careful out there.
ß Division of Chemical Health and Safety of the American Chemical Society Elsevier Inc. All rights reserved.
53