BEIJING -- Beijing's education authority has demanded checks on all school athletics tracks and synthetic sports fields in the capital after they were blamed for mass poisonings of students in at least two schools.

All construction of new school athletic tracks has been suspended, according to a statement by the Beijing Municipal Education Commission on Wednesday.

Last month, dozens of students at the Baiyunlu campus of Beijing No. 2 Experimental School in Xicheng District suffered nosebleeds, dizziness and coughing fits after activity on the school athletics track, which it was suspected had emitted hazardous gas.

Tests on the track this week, nine months after it was put into use, showed excessive amounts of benzene substances and formaldehyde. The track is now covered in a protective coating.

A similar poisoning also occurred on the playground of a private kindergarten in Beijing's Fengtai District recently.

Should the city-wide checks detect any problems with school's tracks and sports fields, these facilities will be made off limits. Those who are responsible for shoddy quality will be punished according to law, the education commission said.

China's Ministry of Education has clear requirements for installation of synthetic racetracks in schools. However, the requirements have not been properly implemented due to lax supervision, the ministry said.