This report provided a listing of synonyms for use with the Hazard Process Index which was developed under NIOSH Contract HSM-99-73-62. During the preparation of the Hazard Process Index, it was noted that a hazard entry could not be easily located in the document unless the exact or listed name was known. There were several synonyms for various chemicals and without a synonym list, it was necessary to consult chemical dictionaries, encyclopedias, or handbooks frequently. In an effort to save time for the ultimate user of the Hazard Process Index, particularly those with little experience, the synonym list was produced. Chemical names, common names, and many trademark names were included in the listing which was a strict alphabetical one, with the exception that structure defining prefixes were ignored in the alphabetization.