Chlorobenzaldehyde phenylhydrazone

A student carried out a new laboratory preparation called the Dipoles Experiment. The student synthesized in three separate phases over a period of one week a chemical similar to a commercially used optical whitener. The student developed an acute dermatitis on her face, chest, arms, and thighs. Six other students, who had also performed the same experiment, developed varying degrees of dermatitis. Skin testing showed that the five of these seven students had positive response to CBPH (chlorobenzaldehyde phenylhydrazone), a chemical used in the last step of the experiment. 

D. F. Barrett. Outbreak of dermatitis among chemistry students— due to alpha-chlorobenzaldehyde phenylhydrazone. Transactions St. John s Hospital Dermatological Society 59 52-55 (1973). 

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