Potentially Teratogenic Gases

Since gases get into the body so easily through the lungs, those that are potential teratogens would appear to be significant hazards for pregnant women. Two of the compounds listed in Table 1 are gases. 

Carbon monoxide (CO) is a deadly poison as well as a potential teratogen. 

It is rarely made deliberately in a chemistry laboratory, but it is produced to some degree whenever organic fuel is burned. Every time a student uses a Bunsen burner, carbon monoxide is generated. The level can be minimized by turning off burners when they are not in use and by making sure that the room is well ventilated. 

Another common gas that appears on the list of potential teratogens is formaldehyde. Since it is normally used as a 40% aqueous solution ( formalin ), it is listed in Table 2 with the organic liquids. Only four of the twenty lab manuals use formaldehyde one in a clock reaction, two to test for the presence of the aldehyde group, and the other to make a polymer of the phenol-formaldehyde type. In none of these is the use of formaldehyde essential. There are other simple clock reactions, there are other less hazardous aldehydes, and there are other polymerization reactions that would be more suitable for an introductory chemistry course. 

Of the twenty potentially teratogenic chemicals listed in Table 1, the ones that appear to present most risk for the pregnant chemistry student are the organic liquids given in Table 2. Some of these (aniline, butanone, carbon disulfide, formaldehyde, and phenol) could easily be omitted from introductory laboratory courses. Benzene and toluene might be substituted by xylene (or perhaps by other hydrocarbons), and both chloroform and carbon tetrachloride could be replaced by methylene chloride. 

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The long-term consequences from mustard gas exposure, particularly at low doses, are unknown. However, a one-time high-dose exposure can result in chronic and recurrent lung and eye problems. Mustard gas is also a known carcinogen, and can cause lung cancer later in life. The ability to cause birth defects in the children of exposed adults is not presently known however, it has the potential to be teratogenic. 

Chlorine (CI2) is one of the more commonly produced chemicals in the United States, and chlorine gas is a potent oxidant that is very irritating and, potentially, corrosive (Wismer, 2007 Kikilo et al., 2008 Smith et al., 2008). Chlorine gas is used as a pulmonary and choking agent, and exposure is frequently associated with moderate to severe painful irritation of the eyes and respiratory tract (Wismer, 2007). Such stressful sublethal exposmes in late-gestational women or animals might be expected to be associated with the induction of premature parturition and, possibly, spontaneous abortion. Oxidative stress can definitely have adverse effects on reproductive function, but the chronic disease usually associated with chlorine gas exposme is primarily related to the ocular and respiratory systems (Smith et al., 2008). The limited information available regarding the reproductive effects of chlorine gas indicates that it is teratogenic (Wismer, 2007). 

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