Let me tell you first and foremost that there is no immediate danger to University of Konstanz students and library staff. There is no reason to panic, none of you need to see a doctor!
Assessing the potential for developing chronic diseases is much more difficult. First, I would like to discuss how any kind of health damage from exposure to pollutants comes about, before discussing related illnesses.
Asbestos must be inhaled to get inside the lungs. It must therefore be present in the room air. During the measurements that were carried out in the library, no asbestos fibres were detected in the air. However, we did find contamination on various items of furniture. Any kind of risk assessment is bound to be subjective, since we do not know at what point and concentration the asbestos fibres were spread throughout the library.
The Federal Office for Building and Regional Planning (BBR) has specified a range of 100 to 150 fibres/m3 (F/m3) of outside air for background contamination with asbestos fibres. Anything below 300 F/m3 is impossible to trace in the air. The fact that no asbestos fibres were detected in the air inside the library suggests that, on average, contamination levels in the library remained below the general background contamination levels.
Unfortunately, we cannot provide threshold values or dose-effect relationships for asbestos. This is because we are unable to tell when asbestos starts to negatively impact the health of those exposed to it. We thus have no choice but to define probabilities regarding health damage that is likely to result from a known exposure time and concentration.
Since exposure to asbestos tends to occur in professional contexts, this information has been obtained from Occupational Safety. The Committee on Hazardous Substances (AGS) advising the Federal Ministry of Labour and Social Affairs (BMAS) has defined risk-based threshold values for handling asbestos (in professional contexts).
The so-called acceptable risk below which exposure is acceptable has been defined as the probability of health damage developing in 4 of 100,000 individuals exposed to asbestos over the course of a 40-year career. By comparison, the risk of being involved in a fatal traffic accident is 2 in 10,000 exposed individuals. For asbestos, the acceptable risk includes concentrations of up to 10,000 F/m3 (everyday exposure over the course of a 40-year career). Another important indicator for assessing medical risks are fibre years. One fibre year corresponds to a daily exposure to 1m asbestos fibres over the course of one year.
The most common illnesses linked to asbestos exposure include lung cancer and malignant pleural cancer, followed by pulmonary fibrosis and pleural fibrosis, both of which result in a stiffening of the connective tissue, as well as cancer of the larynx. The risk of developing cancer of the lung or larynx due to exposure to asbestos doubles after 25 fibre years. We believe that in order to develop malignant pleural tumors, less than one fibre year suffices. The background contamination levels in Germany amount to approximately 0.06 fibre years.
Given the facts and uncertainties attending this particular case, I am inclined to conclude that the risk of contracting a disease is in fact negligible in the long term.
Dr Manuel Fritz
In-house physician of the University of Konstanz