This is the 2nd time that I have heard of something like this happening. The first happened to another youtuber for giving their brushes a bad video review. Again, Coastal Scents responded by stooping low and publicly bashing the woman on their forums in an attempt to discredit her simply because she voiced her opinion on a product. her response video is also in that thread if you want to look through a couple pages. Additionally, it seems like they edit out bad reviews on their site. (I'm sorry, but THERE IS NO PRODUCT IN THE WORLD THAT AT LEAST ONE PERSON WILL NOT LIKE)
Luckily for us, Coastal Scents does not manufacture their products themselves. Their palettes, probably their most popular products, are generic palettes manufactured in China, all of which can be found here and off ebay from Hong Kong sellers (type in "neutral palette" for the 28 piece neutral eye palette and 26 piece eye and blush palette, "lip palette" for their new lip palette, "blush palette" for the blush palette, etc). These are also cheaper on ebay, especially if you buy more than 1 (combined shipping rocks) especially when you figure in how much Coastal Scents charges for shipping...the downside is that it does take longer though (I think I saved over $10 on both neutral palettes though and I refuse to buy from Coastal Scents for the aforementioned reasons..so I think it works for me). Their brushes can be found from their manufacturer, Crown Brushes. The other products I'm not sure where to get.
So now's the fun science stuff: Is silica powder dangerous?
The answer is yes and no. The woman in the youtube video was right about two things: Silica powder CAN cause silicosis, a respiratory disease, if breathed in in LARGE amounts, or through prolonged exposure in small doses over a long period of time (over 20 years) This is also the reason why the people who are producing this stuff have to wear full body suits with masks. However, as you are most likely not going to be snorting this stuff or creating large dust clouds of it to breathe in, you'll probably be fine. Edit: Silicosis has only been linked to crystalized silica particles (the stuff found in pottery, mining, etc) and there is no proof that spherical silica (cosmetic grade) causes or is connected to silicosis. (thanks samanthadread)
Secondly, cosmetic grade silica (silicone dioxide) IS a carcinogen...in lab animals. It's not listed as a carcinogen for humans on the MSDS. So as long as you aren't leaving your container of silica powder out for your pet to snort, you're probably also ok. Other forms of silica are a known carcinogen in humans, however, but they are not as finely milled and therefore cause more damage to the lungs.
Additionally, according to wikipedia, silica is the 2nd most common compound on the planet. (Makes it hard to avoid now, doesn't it?) It's basically quartz or sand, and is found in many, many products besides just our cosmetics. So for those of you who have bought MUFE HD powder or Coastal Scents silica spheres and currently love it, you don't have to toss your beloved powder...just try not to breathe it in :P
For those wondering what exactly silica is used for, a quick google search also turned up the following on uses for silica in cosmetics:
"These are the reasons why silica is used for cosmetics:
Silica contained in foundation adsorbs sweat and oils in skin, which prevents light reflection by sweat/oil and keeps makeup on the skin longer.