We have made a systematic study of the production of elemental CNO in inhomogeneous nucleosynthesis, investigating a much larger region of parameter space than previously studied. We have determined abundances of CNO elements and ascertained the main channels to their production. We have focussed in particular on the role played by the 7Li(n, γ)8Li(α,n)11B(n, γ)12B(β - v)12C reaction sequence: in models with Ωb = 1, we show that this sequence provides the main channel to CNO element production of which there is a significant amount; for lower values of Ωb there is competition from 7Li(α, γ)11B but here there is a concurrent decline in CNO production. From these determinations, CNO element production emerges as a distinct signature of an Ωb = 1 inhomogeneous universe. Beyond 12C, a series of neutron captures is thought to lead to the production of 14C. We have studied the branching at 14C and have deduced the importance of the 14C(d, n)15N reaction which may be the dominant channel for the production of heavier elements.