Occupational exposure of hairdressers to [14C]-para-phenylenediamine-containing oxidative hair dyes: a mass balance study.

We monitored the exposure of hairdressers to oxidative hair dyes for 6 working days under controlled conditions. Eighteen professional hairdressers (3/day) coloured hairdresser’s training heads bearing natural human hair (hair length: approximately 30cm) for 6h/working day with a dark-shade oxidative hair dye containing 2% [14C]-para-phenylenediamine (PPD). Three separate phases of hair dyeing were monitored: (A) dye preparation/hair dyeing, (B) rinsing/shampooing/conditioning and (C) cutting/drying/styling. Ambient air and personal monitoring samples (vapours and particles), nasal and hand rinses were collected during all study phases. Urine (pre-exposure, quantitative samples for the 0–12, 12–24, 24–48h periods after start of exposure) and blood samples (blank, 4, 8 or 24h) were collected from all exposed subjects. Radioactivity was determined in all biological samples and study materials, tools and washing liquids, and a [14C]-mass balance was performed daily.