Sebastian Merkner went only reluctantly to his office. The self-employed carpenter completed Saturdays always his bills because he could then work undisturbed by the daily business. After a few hours in the room he was nervous and felt like charging. Then there were the headaches and eyestrain. The relationship between the office environment and the discomfort was obvious. Merkner went through the possibilities in his head: Was the beams of the wooden ceiling painted with wood preservatives? Escaped from the formaldehyde glued bookshelf? Was the mastic asphalt under the floor covering of the culprit? The master craftsman brooded for months after the causes of his symptoms.