In 2018 and in 2019, the U.S Food and Drug Administration (FDA) found traces of NDMA and NDEA impurities in the angiotensin II receptor blocker (ARB) drug products valsartan, losartan, and irbesartan. The FDA stated "In June 2018, FDA was informed of the presence of an impurity, identified as N-Nitrosodimethylamine (NDMA), from one valsartan API producer. Since then, FDA has determined that other types of nitrosamine compounds, e.g., N-Nitrosodiethylamine (NDEA), are present at unacceptable levels in APIs from multiple API producers of valsartan and other drugs in the ARB class." In 2018, the FDA issued guidance to the industry on how to assess and control the impurities.