The drug is being recalled because the active ingredient has tested positive for N-Nitrosodiethylamineor NDEA, a suspected human and animal carcinogen that is used in gasoline as a stabilizer for industry materials and as a lubricant additive, according to the National Institutes of Health.

The ingredient was made by Zhejiang Huahai Pharmaceutical Company Co. Ltd. The FDA placed the Chinese company on an import alert at the end of September, meaning all of its active pharmaceutical products and finished products will not be permitted to enter the United States. The FDA made that decision after an inspection of the facility.

Several pills that contain valsartan, another drug used by heart patients, have been under a recall since July. The drugs were tainted with NDEA or NDMA, N-nitrosodimethylamine, an impurity that is also considered a possible carcinogen by the US Environmental Protection Agency.

NDMA is an organic chemical used to make liquid rocket fuel and is a byproduct of manufacturing some pesticides and processing fish. It can be unintentionally introduced into manufacturing through certain chemical reactions.

The FDA is testing all heart drugs known as ARBs for these impurities.

Not all medicine containing valsartan is recalled. The FDA keeps an ongoing list of products that are recalled and a list of the valsartan products that are not recalled.

The latest recall impacts less than 1% of the total losartan drug products in the US market, according to the FDA.

If your drug is on the recall list, the FDA suggests taking it until your doctor or pharmacist provides a replacement. Because not all valsartan and irbesartan drugs are involved in the recall, you might be able to switch to a version by another company.

It’s unclear exactly what the cancer risk is if you take the contaminated valsartan pills; the FDA believedthat the risk was low with the valsartan recall.

It estimated that if 8,000 people took the highest dose of valsartan (320 milligrams) containing NDMA from these recalled batches daily for four years, there may be one additional case of cancer over the lifetimes of 8,000 people. Many patients take a much lower dose of valsartan, and therefore their risks are theoretically much lower.

The FDA said it will continue to test all products containing valsartan and similar drugs for the presence of impurities.