HPR ROV has developed a bespoke gas sampling unit which is attached to one of our micro ROVs. The unit collects sub-surface gas into sealed bags which are resistant to a wide range of chemicals, including most acids and acid mixtures, weak bases, halogens, halogenated solvents, hydrocarbons, alcohols, salts, and oxidants. The gas sampling system is recovered to the surface, valves on the bags closed before the sample bag is sealed in a separate bag and delivered to the client in a Peli case for dispatch to a laboratory shore for analysis.