French drugmaker Sanofi announced Friday that it has called back the popular over-the-counter heartburn medication Zantac from retailers in the U.S. and Canada to investigate a possible carcinogen in the drug. The recall is a precautionary measure. 

"The recall is being taken due to the possible contamination with a nitrosamine impurity called N-nitrosodimethylamine (NDMA)," Sanofi said in a statement. Sanofi added it is committed to transparency and will continue to release information gathered with health officials.

The U.S. Food Drug and Administration said on Sept. 13 that low levels of NDMA could be found in some Ranitidine medicines such as Zantac. The FDA did not identify any specifically affected product and there were no immediate recalls. Ranitidine is intended to decrease stomach acid production.

Sanofi will conduct tests of the drug to see if NDMA is present, in order to comply with the FDA. NDMA is classified as a probable human carcinogen. Major U.S. retail chains like Walgreens, CVS and Walmart had previously announced they would stop selling Ranitidine drugs over the NDMA concerns. 

In September, Apotex Corp. voluntarily recalled its 75 mg and 150mg Ranitidine tablets over NDMA impurities, as a precautionary measure. 

In June, pharmaceutical company Valisure alerted the FDA to its findings that linked Ranitidine drugs with NDMA. Valisure, which had conducted studies with Stanford University, found that all Ranitidine medications could generate high levels of NDMA in the human body.

Valisure CEO David Light believes "there is no way to fix the drug, the drug itself is the problem" and that there is "no acceptable cancer risk" for Ranitidine drugs. 

The issue with the drug isn't just in North America. France's top drug safety regulator has also issued a recall of Zantac tablets.