Last game a question came up regarding toxic gas and maybe other item cards. It is obvious that you discard the toxic gas card back under the search deck when you pass the skill check. But what happens when you fail the check? Do you keep the item and are able to try again later or do you have to discard it?
I would say you only have to discard it, when you pass the skill check. It is not exactly stated in the rule book. But for items with limited number of uses it is written, that you put a wound marker on it when successfully triggered. So I would transfer that to one use items.