2020, new FDA testing and evaluation prompted by information from third-party laboratories confirmed that NDMA levels increase in ranitidine even under normal storage conditions, and NDMA has been found to increase significantly in samples stored at higher temperatures, including those at which the product may be exposed during distribution and handling by consumers. The testing also showed that the level of NDMA increases as ranitidine medication ages. These conditions may raise the NDMA level above the acceptable daily intake limit. Some evidence indicates that NDMA may form from the degradation of ranitidine itself with increasing levels seen over its shelf life. Whether NDMA can also be formed from ranitidine inside the body is unclear. Some studies suggest that it can, while others do not. Given the uncertainties, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) recommended a precautionary suspension of these medicines in the EU. In August 2020, the EMA provided guidance to marketing authorization holders for avoiding the presence of nitrosamine impurities and asked them to review all chemical and biological human medicines for the presence of nitrosamines and to test the products at risk. In September 2020, the FDA issued guidance about the control of nitrosamine impurities in human drugs. An implementation plan was issued in February 2021. List of recalls In September 2019, Apotex recalled all over-the-counter ranitidine tablets sold in the United States at Walmart, Rite Aid, and Walgreens. These retailers, along with CVS, removed Zantac and some generics from their shelves. On 8 October 2019, the Medicines and Healthcare products Regulatory Agency of the United Kingdom (UK) issued a drug alert for ranitidine "... to proactively communicate the recall to hospitals, pharmacies, dispensing practices, retailers and wholesalers in the UK." This included all Zantac-branded preparations, along with all generic preparations of ranitidine from Teva UK Limited, Rosemont Pharmaceuticals Limited, Omega Pharma Limited and Galpharm International Limited, Perrigo Company plc, Creo Pharma Limited and Tillomed Laboratories Limited, OTC Concepts Ltd, Relonchem Ltd, Noumed Life Sciences Ltd, and Medreich Plc., Accord Healthcare, Medley Pharma Limited, and Medreich Plc. On 15 October 2019, the Department of Health and Social Care of the United Kingdom issued a supply distribution alert (SDA/2019/005) for all oral formulations of ranitidine. In October 2019, Sanofi recalled all over-the-counter Zantac in the United States and Canada, Perrigo issued a worldwide recall of ranitidine, Dr. Reddy's issued a