Polychlorinated biphenyls (PCBs) are a group of closely related chemicals that can be harmful to health. In Denmark, they were used in construction between 1955 and 1977. You can neither see nor smell PCBs, but if a building was constructed or renovated in the period 1955-1977 and there are visible sealants of the elastic type, one should be on guard.
PCB is a substance that accumulates in the body. It can be absorbed by ingestion, through inhalation and via skin contact. In buildings in which there are PCB-containing building materials, a PCB is delivered into the air and thus absorbed into the body through inhalation.
Prolonged exposure to PCB in large amounts may cause damage to the liver, immune system and nervous system, and PCBs are also hormone disruptive and potentially carcinogenic.
The Knowledge Centre for the Working Environment of Copenhagen has produced a checklist for PCBs (link provided). If you can answer yes to any of the questions in the checklist, there is sufficient reason to investigate if there are PCBs in the building.
PCBs - various substances