After U.S. health officials said they detected low levels of a potentially cancer-causing chemical N-Nitrosodimethylamine (NDMA) in popular heartburn treatments such as Zantac, the Ministry of Food and Drug Safety collected and inspected ranitidine-containing drugs on Sunday.

“We are gathering and examining products in local distribution. We will take action when the results come out,” a ministry spokesman said.

According to the U.S. Food and Drug Administration Friday, the authorities found NDMA in ranitidine-class medications including Zantac. NDMA is a carcinogen that had been detected in some valsartan-containing hypertension treatments in Korea.

As the NDMA contamination was at a low level, the FDA did not order a suspension of the medication or recall and was reviewing the drug’s safety.

Ranitidine, known for popular drug Zantac, is effective in peptic ulcer disease, gastroesophageal reflux disease, and gastritis. Ranitidine 75mg is an over-the-counter drug. In Korea, GSK distributes Zantac.

“When the test results come out, we will inform the public,” the ministry official said. “Depending on the results, we will decide whether to establish provisional criteria for NDMA levels in ranitidine, as in the case of valsartan.”

After the government suspended and recalled some valsartan-containing medicines due to carcinogen risk last year, the ministry set up criteria of NDMA levels for six raw materials and finished goods in sartan drugs.

Under the criteria, NDMA level should not exceed 0.3 ppm in valsartan, 1.0 ppm in losartan, 2.4 ppm in olmesartan, 0.3 ppm in irbesartan, 3.0 ppm in candesartan, and 0.8 ppm in fimasartan.