A British medical professional, Nahaniel Henshaw, proposed what would've been the 1st hyperbaric chamber for medical treatment of people in 1662. The steel container was to have already been pressurised with air, which at time wasn't yet recognized to incorporate oxygen, later on learned by Carl Wilhelm Scheele all-around 1770 https://oxygenchamberstherapy76838.bloggosite.com/43651581/5-essential-elements-for-oxygen-treatment-cost