A method for examining at least one wafer (13) with regard to a contamination limit, in which the contamination potential of the resist (13a) of the wafer (13), which resist (13a) outgasses contaminating substances, is examined with regard to a contamination limit before the wafer (13) is exposed in an EUV projection exposure system (1). The method preferably includes: arranging the wafer (13) and/or a test disc coated with the same resist (13a) as the resist (13a) of the wafer (13) in a vacuum chamber (19), evacuating the vacuum chamber (19), and measuring the contamination potential of the contaminating substances outgassed from the wafer (13) in the evacuated vacuum chamber (19), and also comparing the contamination potential of the wafer (13) with a contamination limit. An EUV projection exposure system (1) for carrying out the method is also disclosed. By rejecting wafers having an especially high contamination risk, the contamination of optical elements in the projection exposure system (1) on wafer exposure may be distinctly reduced.