Heavy water, or deuterium oxide (D2O), is available for civilian purchase, and while it is not heavily regulated, its export is restricted due to potential nuclear applications. Deuterium is a stable isotope of hydrogen and chemically similar to regular water, making it safe to drink in small quantities, though it can be slightly toxic in large amounts due to its effects on metabolic processes. The legality of owning heavy water appears to be less stringent than initially thought, as it is commonly used in scientific research. Tritium, another hydrogen isotope, is more heavily regulated due to its radioactive properties. Overall, while there are some concerns regarding heavy water's effects on health and its regulatory status, it remains accessible for civilian use.