According to U.S FDA standards, what is the required purity percentage for medical oxygen?

The required purity percentage for medical oxygen, according to U.S. FDA standards, is 99%. This high level of purity is crucial because medical oxygen is used in various therapeutic settings, including hospitals and home care, to support patients with respiratory difficulties. Ensuring that the oxygen is at least 99% pure helps to minimize the risk of contamination that could potentially harm patients, as impurities can lead to various health complications or reduce the therapeutic efficacy of the oxygen being administered. High purity levels also contribute to patient safety and the effectiveness of the medical treatments involving oxygen therapy.

The other options, while close to the correct answer, do not meet the strict purity standards mandated for medical applications. Values lower than 99% could introduce unacceptable levels of contaminants, which are not permitted in the context of medical oxygen storage and delivery.