Authorities are suspending sales of 13 types of capsules with reported chromium contamination and are checking the factories accused of producing them.

The State Food and Drug Administration issued an urgent notice on Sunday to suspend sales until safety is tested.

Police in Xinchang county, Zhejiang province, where China's largest capsule-manufacturing base in Ru'ao township is located, detained 22 people from four capsule factories on Monday, according to Xinhua News Agency.

Meanwhile, the administration and local authorities conducted inspections on 43 capsule factories in the county, closing those exposed by a China Central Television investigation to have made empty capsules using gelatin containing excessive chromium and selling them to pharmaceutical companies.

The CCTV report showed that the industrial gelatin used to manufacture the capsules was made from scraps of leather material. The report said the gelatin came from companies in northern Hebei province and eastern Jiangxi province.

Officials in Fucheng county, Hebei, where a factory called Hebei Xueyang Gelatin and Glair Factory was found to be providing capsule makers gelatin made from tanned leather, told China News Service on Monday that the county has suspended the production of all its gelatin makers for an inspection.

However, a fire broke out in an office building in the Xueyang factory on Sunday as police were about to enter it to investigate its production activities. Computers, receipts and other paper documents were all burned, though some remnants showed that the burnt documents possibly kept records of its gelatin trades, the report said.

The cause of the fire is under investigation.

Some drugstores in Beijing took the medicines off their shelves after the news broke.

A staff member of Hedantang Pharmacy, a drugstore in Chao-yang district, said the store has received notification from food and drug authorities to stop selling all 13 batches of medicines.