Grotrian diagram showing the He I energy levels. The 1s2s ³S–1s2p ³P 1083 nm transition could produce a 1 μm P Cygni feature in NLTE models (e.g. Tarumi et al. 2023) because 1s2s ³S can be difficult to ionise (e.g. requiring UV photons < 260 nm) and the natural transition to the ground state is very slow (e.g. characteristic timescale of hours). However, as shown here, the other well-populated triplet state, 1s2p ³P, is several orders of magnitude more susceptible to ionisation and naturally decays to the ground state 10⁶ times faster, on a timescale of 0.01 second.