Applications In addition, paraformaldehyde is used as a fungicide and bactericide in industries as varied as crude oil production, beet sugar refining, and warehousing. Paraformaldehyde has widespread acceptance as an additive to stop fermentation of the starch on oil-well-drilling muds. Description nounChemistry. a white, crystalline polymer of formaldehyde, (HCOH)n, from which it is obtained by evaporation of the aqueous solution:…