Having stored rice without mylars in the very evil, conspiratorial and cancer causing COLORED buckets for almost 20 years now, I can tell you no one in our family has grown a third arm, started speaking in tongues or went sterile.
I'm afraid that whole "dye" thing is BS. Never found anything truly substantial on it. I would use white IF you can find it however, just because of the fact that it REFLECTS rather than ABSORBS light and therefore heat.
Call up Ropakco or one of the huge bucket manufacturers, tell them you are planning on packing food for long term storage in there buckets, which type of bucket would they recommend. They will recommend an HDPE 2 bucket to you.
What does Walton and the other big packers use? Buckets with HDPE 2 on the bottom of them. Look it up in James Stevens (a recognized expert in the food storage industry) book.
Simple and easy test- look at some of the thinner plastic food containers in your fridge, they are usually HDPE 2 or 3. 3 being the thinner plastic like used in your ketchup container. Would big corporations that have teams of lawyers working around the clock chance a huge lawsuit just because of colored plastic? Come on.
I've seen this come up before, it's internet conjecture. If your concerned about "dyes" go with white buckets only. There's benefits to both if you really think about it-
White buckets are going to REFLECT (versus absorb) light. A good thing.
However, the camo buckets or the green buckets you see at the sporting goods stores may BLEND IN better in the woods or a rural area if bugging out with a bunch of buckets is an issue.
Gasketed lids are important. You don't have to have gamma seal lids though. Folks this has come up time and time again but your product will NOT simply disintegrate or vanish into thin air 5 minutes after you open the bucket and mylar!!! We made some bread on Saturday (we don't do it nearly as often as we should) and I looked at the bucket and asked the wife- "when did we open this?" Best we could figure early last year or so. The wheat had not: 1. Got weevils. 2. Disintegrated into a powder and then vanished when I opened the lid.
The wheat was and is still in the same form it was when we packed it in 98-99.
THAT'S why you want to use mylars and o2 absorbers, so your food WILL be ready to go when you need it.
Watch the video Protus linked to, it will answer a lot of questions.