Health Canada has issued a recall for several Valsartan-containing antihypertensive medications due to contamination with a potential carcinogen. An impurity, N-nitrosodimethylamine (NDMA), was found in the valsartan used in these products. The valsartan was supplied by Zhejiang Huahai Pharmaceuticals. NDMA is a potential human carcinogen, which means that it could cause cancer with long-term exposure.