Some 130 people were taken to hospital and more than 100 schools closed Monday in southeast Iran after an incident at a sewage works caused an outbreak of poisonous gas.

A man has been arrested on suspicion of dumping expired pesticide which reacted with water to produce a noxious gas that left people with breathing problems, headaches, dizziness and vomiting.

The problems in Zahedan, in Sistan-Baluchistan province, led to 109 schools being closed and 60 pupils and three staff were affected, an education official told the official IRNA news agency.

With winds blowing gas into the streets, a total of 130 people were taken to hospital, Mahmoud Imani, deputy director of treatment at Zahedan Medical University, was quoted as saying.

Some of those affected have since been released, the report said.