Full face diving masks are designed to have an air flow that helps minimize CO2 buildup[0]. The greater concern is that they might leak due to not fitting prope

Full face diving masks are designed to have an air flow that helps minimize CO2 buildup[0]. The greater concern is that they might leak due to not fitting properly, and/or the user might panic and pull the mask off while underwater. [0] http://www.opstechnologies.com/products/scuba/full-face.html http://www.opstechnologies.com/products/scuba/full-face.html