I bought a bunch of the 55g barrels that had olives shipped in.
I would think they are food safe. I've been using them for about 15 yrs now.
I start my water in these to age it and then transfer the water to the 26g containers after aging, to make the salt solutions and top up water from.

Hi Mark, seems to me I may have answered this before, but happy to oblige, maybe with more details this time.

Two blue barrels originally filled with glycerine (by product of manufacturing bio diesel) I purchased early this year at Swan Lake Nurseryland for $24 each. I haven't been there all summer and last time I was there, they had none left. The glycerine is used to make that skin friendly soap the ladies like. They were sold as rain barrels and that's what I'm using one of them for. The second one I've used to store RODI waste water for subsequent use in the garden or whatever. I still notice a bit of foam buildup when pumping water out of these barrels so I'll need to take a pressure washer or steam the inside to get all the glycerine residue out before contemplating their use for RODI water.

One whitish translucent and slightly heavier guage barrel I got from Mad Capper's Brewhouse on 29th Str around 43rd Ave. I'm a customer there and go about every month & a half to order up a batch of beer. Burt charged me $40 for the barrel I have. These have malt or adjunct in them and are definitely food safe but will also need to be steamed to get all the sticky, sugary goo out of them. When I was there about 3 weeks ago he still had a black one sitting there empty. I preferred the translucent one for the ability to see the liquid level in them. These have level marks molded into them at 5 gal intervals... which doesn't really help me at the moment since I decided to build a rack and have it laying on its side. The advantage to that is I'm able to use the two water tight openings for filling and draining. The caps are threaded and can be drilled out to fit adapters for a ball valve or whatever you decide you want on there.

I'm sure if you check the phone book, you'll find a number of other brew on premises businesses in Vernon. They will all have some of these barrels empty at one time or another. I've even been considering going to one of the big box supermarkets and asking about the 'olive' barrels. Might even get them for free there.

Thanks Mike, you had mentioned Swan Lake before but when I went there, they said they had none left and no ETA on ever getting more.

I will check out your other suggestions.