BEIJING -- China has tightened the sale of dangerous chemicals during the Olympics, ordering those who buy such substances to register under their real names.

The rule, which was enforced on July 12, will be effective until September 30, according to a circular jointly issued by the State Administration of Work Safety and the Ministry of Public Security.

On the list of dangerous chemicals are more than 10 categories including perchloric acid, nitric acid and nitrate, fuel reductant and metal oxide.

According to the circular, companies that buy such chemicals must produce the photocopies of the companies' business licences and and the identity cards of the people who do the transactions.

Companies that sell such chemicals must have permits to produce or sell them, and they must strictly check and register the purchasers' identity licences and cards.

They must also file all the information about the purchasers, including their addresses, transaction dates, the chemicals' names, quantities, and what they are used for. Selling to people with no identity cards will be strictly prohibited.

Relevant departments of local governments at various levels must beef up the management of the producers and sellers of such dangerous chemicals, the circular said.

Those who have resulted in accidents due to their negligence will be severely punished, it said.

The Beijing Olympics will open on August 8.