The Netherlands National Institute for Public Health and the Environment published a report in December 2016 saying that the health risk from playing on artificial fields, which are common throughout the Netherlands and elsewhere as low-maintenance alternatives to natural grass, is "virtually negligible."
The Dutch soccer association welcomed the findings, saying they gave clarity to sports clubs and players. Many clubs across the Netherlands had stopped playing on rubber crumb fields since a television program in October raised concerns about health risks.
"The uncertainly about playing soccer on synthetic grass with rubber crumb is gone," the Royal Netherlands Football Association said in a statement. "Footballers, parents, clubs and the KNVB can move on. The signal is safe."
The Dutch investigation tested 100 sports fields and examined a wide range of scientific literature. The organisation said it will carefully study American research expected in late spring 2017 into the fields.
"No indications were found in the available literature of a link between playing sports on synthetic turf fields with an infill of rubber granulate and the incidence of leukemia and lymph node cancer," the Dutch study said. "No international research has demonstrated this connection."
It added that chemicals linked to causing such cancers are either not present in the rubber crumb or are present in very small amounts. Tests conducted for the study also showed that chemical substances in the crumb were released in very low quantities.
"This is because the substances are more or less 'enclosed' in the granulate, which means that the effect of these substances on human health is virtually negligible," the report said.