Theoretical study on the limit for rubber shock-absorbing tiles
Shock-absorbing rubber tiles are usually made from discarded car tyres and contain polycyclic aromatic hydrocarbons (PAHs). These are harmful substances that can be found in rubber articles, among other things. For the safe use of rubber articles such as shock-absorbing tiles, producers have to comply with the European limit which has been set for PAHs in consumer products.
Aim of the study
The reason for the study is the tightening of the product limit for PAHs in rubber articles in 2015. The results of this study can be used in the evaluation of the product limit for PAHs in all plastic and rubber consumer products by the European Commission in 2017. In this evaluation, RIVM considers it important also to take into account exposure to PAHs from other consumer products.
Due to several uncertainties, the present risk assessment is only an indication of the risk of cancer. One of the uncertainties is the lack of reliable data regarding the exposure of playing children to the tiles. These include data on the duration and frequency of skin-tile contact and the quantity of PAHs released from the tiles.
In addition, there is no agreement among scientists on the best method to extrapolate the risks of cancer from animal studies to humans. RIVM recommends initiating a discussion at the international level to obtain agreement on the subject. This study can contribute to this.
Risk assessment of cancer-causing substances
In general, the risks from the exposure to cancer-causing substances are indicated as the extra number of people who develop cancer per million of exposed people; the term ‘extra’ is used as people have the risk of developing cancer without this exposure. An extra risk of 1 in a million exposed people is regarded as negligible in the risk assessment of cancer-causing substances.
Because of the uncertainties mentioned above, the calculated extra cancer risk due to exposure to rubber tiles is presented as a range, meaning that the extra risk lies between two extreme values. At the worst-case extreme value, the negligible risk level is slightly exceeded. Based on the calculations performed, it can be concluded that it is safe to play on tiles that comply with the consumer limit.