Objectives Two spa workers reported such symptoms as fever, shivering, palpitation, arthralgia, and diarrhea after performing seaweed massages on clients at a spa center. This study was carried out to determine whether the symptoms were related to exposure to endotoxin.

Methods Personal and stationary air sampling for the measurement of airborne endotoxin was carried out at the spa during the preparation of a bath and the following seaweed massage. In addition, the impact of storage time on the concentration of endotoxin in the seaweed was investigated.

Results The measurements confirmed exposure to aerosolized endotoxin at the spa (11 ng/m² and 22 ng/m³). The endotoxin concentration in the stored seaweed increased as the storage time increased, from 360 ng/g seaweed for fresh seaweed to 33100 ng/g seaweed for seaweed stored for >20 weeks.

Conclusions Organic dust toxic syndrome was diagnosed for two workers who performed seaweed massages at a spa center at which aerosolized endotoxin was measured. In order to minimize entotoxin exposure during massages, it is important to use fresh seaweed or seaweed kept well cooled for no more than 2–3 weeks.

Key terms Fucus serratus; algae; case report; endotoxin; exposure; measurement; occupational endotoxin exposure; occupational exposure; seaweed; spa; work-related disease