Playing football on artificial turf may be dangerous to footballers' health, according to Zembla. Almost all artificial turf fields contain rubber granules, which have been linked to cancer. 

Scientists told Zembla that the use of rubber granules in artificial turf was never properly investigated. And this while the United States and Britain link it to footballers getting cancer.

Rubber granules are made from old car tires and contain carcinogens. There was a study in 2006 to see whether these substances can enter football players' bodies. But according to Zembla, that was a very brief study.

As the granules are recycled car tires, another problem is that the rubber granules manufacturers don't know exactly which substances are present in the product and at what quantity.

The KNVB is calling for further research into artificial turf containing rubber granules. The scientists that spoke to Zembla agree. They go even further saying that artificial turf should not be played on until all the risks are clear.

National health institute RIVM and the Ministry of Public Health, Welfare and Sports state that there are no health risks in using these types of fields.

According to NU.nl, the number of artificial football turfs increased from about 300 in 2007 to around 2 thousand this year. 90 percent of them contain rubber granules.