During the summer and autumn of 2012, the Swedish Chemicals Agency inspected some thirty companies in Sweden that import motorcar tyres. The companies were asked to describe how they work to ensure that imported tyres do not contain polycyclic aromatic hydrocarbons (PAHs) at levels that are prohibited.

PAHs are a large group of substances and many of them have properties that are hazardous to health and the environment. They are persistent, bioaccumulating and carcinogenic. PAHs can be found in aromatic extender oils (high PAH oils) used as plasticisers in rubber and tyres. When tyres are worn they emit particles containing PAHs, which can cause damage to humans who inhale them or in the environment when spread through the air to land and water.

The European Trade Association for the Rubber and Tyre Manufacturers (ETRMA) has also made analyses of tyres on the European market. In their study, 204 tyres were analysed. 21 of these did not meet the concentration limit for PAH. 20 of these tyres were made in China.