In this work, we study the hydrogen introduced into InP during methane/hydrogen/argon reactive ion etching (RIE) to determine its effect on metalorganic chemical vapor deposition regrowth. We replace hydrogen with deuterium and confirm that deuterium is introduced into the substrate during methane/deuterium/argon RIE with secondary ion mass spectrometry. During regrowth, the deuterium diffuses from deep within the material and clusters at the regrowth interface, strongly indicating the presence of defects. To further understand the role of hydrogen, we investigate the separate effects of ion damage and hydrogenation on subsequent regrowth. We find that photoluminescence of regrown quantum wells is greatly improved on argon ion damaged substrates which have been additionally exposed to hydrogen at -150 V for 3 min. These experiments illustrate that hydrogen interacts with defects in InP, preventing their propagation during regrowth, and improving the photoluminescence quality of regrown quantum wells.