China’s Zhejiang Huahai Pharmaceutical for years enjoyed the upside of the U.S. pharmaceutical market, selling its valsartan API to drugmakers producing blood pressure meds for the market. Now it is seeing the downside, having its products banned by the FDA and facing litigation over the discovery of a suspected carcinogen in its API.

The Chinese company disclosed (PDF) to the Shanghai Stock Exchange that it has been named in multiple lawsuits, according to a translated copy of the filing. The disclosure says Huahai has been named in lawsuits in Missouri, New Jersey, Illinois and New York with allegations including gross negligence, fraudulent concealment, breach of contract and unjust enrichment.

The FDA on Friday said it has put Huahai on its import alert list, banning its products from the U.S. The company, whose APIs are in about half of the valsartan blood pressure medicines sold in the U.S., last summer instigated a global recall of its products.