Not sure exactly where in the GTA you are, or what time you posted. If it after hours for most of the welding and fire and safety places (best to call around with the yellow pages in one hand), TSC stores carry welding gases. Canadian Tire will refill paint ball gun CO2 cylinders. Both are much more conveinent IMO. I work in a small town and its an hour to everything but those stores. But then thats the beuty of living in the middle of nowhere I guess Then there's the two paint ball fields....$10 worth of parts and I converted my regulator to use a paint ball cylinder.