The labour conditions at an experimental dicyclopentadiene (DCPD) processing line was characterized by a combined action of occupational hygienic factors, mostly contamination of the working zone air with chemical substances. Both to the degree of its hazardousness and concentration levels in the working zone air, DCPD was predominant agent in the gaseous discharges. The DCPD discharge in the air was due to improper pump packing gland hermetization, manual sample taking, inadequate decontamination of the equipment prior to preventive maintenance, as well as to the desorption by the construction elements surfaces. DCPD contamination of the workers' skin and overalls was also revealed.