gaz toujours présents

OBS: Problème de traduction ici. Il est question de repérer les zones où des gaz sont toujours présents, ou, encore, où des gaz subsistent toujours. Bref, des zones de poches de gaz restants.

CONT: Since all of the kill and active mud had been lost, it was no longer feasible to combat the gas flow ... During the ensuing five days, various advance parties boarded the Kulluk during daylight hours to determine the areas of lingering gas and to vent those areas.