Our results demonstrate an increasing risk of irritative symptoms up to a level of 0.2-0.3 mg m(-3) of trichloramine. The health data in our study, as well as the review of the literature, strongly suggest fixing the trichloramine occupational exposure limit at 0.3 mg m(-3). Severe technical standards (on flocculation, filters, water flow, and ventilation systems) and regulations on water quality (free and combined chlorine, urea, and amount of fresh water) contribute to reducing trichloramine formation and, consequently, occupational and public trichloramine exposure. In addition, to ensure good public hygiene (showering before swimming), correct and regular public awareness campaigns should be undertaken.