Authorities in north China's Hebei Province said on Thursday that they will crack down on sub-standard rubber products after reports linking school running tracks to the ill health of students.

Authorities in Baoding City will inspect factories to find which ones are using poisonous materials.

In Cangzhou, authorities have already suspended production of rubber granules at nine firms, and seized equipment and materials for testing. It is also questioning executives at these firms over the source of their raw materials and the sale of products.

Students at a Beijing primary school earlier this month fell ill, with symptoms such as nose bleeds, after the school renovated its playing fields.

Though tests showed the rubber used in the track and air quality in most part of the school met national standards, it prompted authorities to launch checks nationwide.

The Education Ministry also pledged to hold people accountable for allowing hazardous materials to be used for school tracks.

source : xinhua