This paper describes a study of the outgassing from the pinch-off of copper tubulations. The gas released is approximately 99.5%CO2and 0.5%O2. The amount of gas varies with the type of copper, its diameter, and the treatment given to the tubulation prior to the pinch-off. The amount of gas can vary from1×10−6 cm3(STP) for 0.250 in. o.d., 0.182 in. i.d. OFHC tubulations that have not been cleaned or baked, to3×10−9 cm3(STP) for the same tubes that have been chemically cleaned, and then baked on the vacuum system. Refrigeration tubing showed the same initial amount of outgassing, but still outgassed3×10−8 cm(STP) even after cleaning. With careful treatment,0.125 in. o.d.×0.080 in. i.d.OFHC tubulations release less than3×10−10 cm3(STP) of theCO2–O2mixture during a pinch-off.