Predicted ice compositions by the KMC simulations for NIR38. For models 6 (n_H = 2 × 10⁵ cm⁻³, t_col=10⁶ yr), 8 (n_H = 2 × 10⁶ cm⁻³, t_col=10⁵ yr) and 9 (n_H = 2 × 10⁶ cm⁻³, t_col=10⁶ yr), the final abundances are taken from simulations that completed 96.8, 99.5 and 94.7% of their intended collapse times, respectively. Missing bars indicate ice abundance ratios ≤0.03% relative to H₂O.