Abstract: An air contamination detector for a scuba unit includes a transparent tube having a lumen, the lumen being user visible for a full 360.degree. about its circumference. A contamination indicator is positioned within the lumen and is exposed to air flow from the air supply of the scuba unit. The contamination indicator is responsive to a contaminant to manifest a change that is visible through the transparent tube. A quick connect/disconnect air connection is affixed to one end of the transparent tube and mates with a low pressure fitting that communicates with the scuba air tanks. A further quick connect/disconnect air filling is positioned at another end of the transparent tube and is connectable to a hose that provides air inlet control for a buoyancy control vest.