Yamamoto Chemical Industry Co., a major Japanese manufacturer of pharmaceutical chemicals, has shipped acetaminophen to drugmakers after mixing in Chinese-made stocks of the same chemical without the proper paperwork, health ministry officials said Thursday.

A chemical analysis of the distributed by Wakayama Prefecture-based Yamamoto Chemical found no problems with its quality, and no health damage has been reported, the officials said. Acetaminophen is commonly used in cold medicines and also known as paracetamol.

The Ministry of Health, Labor and Welfare conducted an on-site inspection of the company in May together with the prefectural government, on suspicion it had violated the law on securing the quality, efficacy and safety of pharmaceuticals and medical devices.

The local government plans to discipline the company by imposing administrative measures.

The company has currently placed on hold shipments of all of its products. A Yamamoto Chemical official told Kyodo News that “a representative is not available,” declining to comment on details.

Yamamoto Chemical added cheaper acetaminophen imported from China to its own acetaminophen, which is made mainly from U.S. basic ingredients, before shipping the product to drugmakers.

But the company had failed to file papers with the Pharmaceuticals and Medical Devices Agency, which screens medicines for regulatory approval, for importing the Chinese ingredient, according to the officials.

The company has told health ministry officials it began blending the Chinese-made component in some products several years ago, apparently aiming to reduce production costs.

The inspection has found that the pharmaceutical chemical maker has not kept records on the manufacture of some products, including acetaminophen, although it is required to do so by law.

The ministry discovered little difference between the products containing the Chinese-made pharmaceuticals and products supplied by other makers in the domestic market.

Therefore, the ministry believes there is no safety risk, and does not see the need to recall the medicines.

Wakayama Gov. Yoshinobu Nisaka said Thursday the local authority would “deal strictly with the matter in accordance with laws.”