We have realized reliable 2.3-mum wavelength InAs-InP multiquantum-well distributed-feedback (DFB) lasers for trace gas monitoring applications. The estimated median lifetime exceeds 1x105 hours during aging at an ambient temperature of 45degC and with a constant output power of 3 mW. Furthermore, the relative increase in operating current is proportional to the square root of time, and it is clarified that the main degradation mechanism in DFB lasers with highly strained InAs quantum wells is dominated by a diffusion process as found with conventional telecommunication lasers.