There are no current government approvals for specific brands of airsoft bb.
The only current concern has to do with biodegradability, and more importantly, non-toxicity. Most "bio" products are a mix of PLA and mineral powder and starch as a binder. Some brands add an enzyme to enhance the speed of degredation - we think thats stupid - anyone who played at Claybank last year, or anyone who has been forced to play in 100% humidity (welcome to Muskoka) will tell you, you want it degrading on the ground, and not in your mag or barrel. Enzyme additives are for marketing, but there are plenty of BBB ECO bags out there half used from last season, and they're still good to go. So while there might be a marginal price difference, we think the thought and engineering behind the product is worth the value we offer.
Governments dont regulate airsoft bbs - they regulate what can be left on land before it has to be remediated. And that is up to the current landowner. The idea that one bb is approved over another is only valid insofar as its composition. ABS Styrene is a moncyclic aromatic hydrocarbon - big bad petrolium base. It will require remediation if used on land - the ratios vary from jurisdiction to jurisdiction. So being approved really has more to do with having a bio friendly formula that eliminates remediation. Compositions that meet that criteria in a 6mm package between .20 and .30 grams limit what you can use. The distinction then becomes manufacturing for fit and finish. Thats where BB Bastards are (in my belief and experience) the best choice you can make that meets quality for cost.
As Blackthorne said, we're always willing to look at serious test results and claims backed up with fact. Present your research and identify your methods and we'll take you seriously. Outside of that, well, its opinion. There is lots of anecdotal evidence in this thread that supports BBB. If you want more stringent, look to CDN_Stalker's thread, as well as what we post on our website and here. We are transparent about is because airsofters figure stuff out pretty quick and outright marketing without substantiation lasts about as quick as a smarty on a fat farm.
My 2 cents. Cheers. And enjoy airsoft - with whatever brand you shoot. All we ask is you give us a chance to have your business. We'll give you a good product at a fair price with a money back guarantee. We do that because we KNOW you will be happy with our product.