Pickering C A, Moore W K, Lacey J, Holford-Strevens V, Pepys J
Clin Allergy. 1976 Mar;6(2):109-118. doi: 10.1111/j.1365-2222.1976.tb01888.x.
This paper describes the investigation of respiratory disease presenting in a group of men employed on the printing floor of a factory. The air-conditioning units supplying this floor were found to be contaminated with a variety of micro-organisms. The specific cause of the disease was not identified but an alteration in the system of humidification led to the complete resolution of symptoms.