To understand the wood-fuel contamination problems faced by the ancient glass industry, some Roman glass fragments and beads were analysed for carbon by the elegant, non-destructive deuteron activation technique based on C-12(d,n)N-13 nuclear reaction. Carbon was found in all analysed glasses, covering a mass concentration range from 160 ppm to 2.2%, indicating that some fuel contamination was present in all samples. The higher concentration of 0.94 to 2.2% observed in some beads indicates that carbon was added intentionally as a “component” to the glass melt to obtain an amber colour.