Sandbagged

I've heard before that there are dangerous types of sandbox sand, in fact, I've successfully bought washed river sand before because it's supposed to be safer (you know, the smaller bags of sand, the ones that cost 4x as much, and get snapped up in the first day they're put out?). But we had a few fabulous sunny days last week, and my kids are now addicted to being out on our patio playing in the 'box, so I thought I would run in quickly and grab some fresh sand before the waves of Asian Tiger mosquitos hit. It's early, right? It's not like I am trying in August so I should have a stab at a couple of the 14 bag-supply due to hit the DC area. After hitting up one hardware store and two garden supply stores, I am left with a resounding sense of frustration and it's not that I didn't let my fingers do the walking. Can anyone please tell me why it is acceptable to have this warning label on a product labeled Play Sand? Marketed to children?

"This product contains small amounts of crystalline silica (CAS 148 08-60-7), a common mineral found in natural sands and stones. Excessive inhalation of respirate silica dust may cause cancer and lung disease. Avoid breathing dust. Wear appropriate respirator in dusty areas. First aid: move to fresh air." (emphasis mine)

The Green Guide basically says to keep your kids out of the sandbox (and off the asbestos laden pressure treated wood playsets for that matter). I can't do that. I mean, I survived sitting in the back of my parents' wood-paneled station wagon (the one with the rusted-out bottom floor we used to poke our feet through to run in place, Flintstones-style, at stoplights). So obviously I cannot deprive my children of the basic pleasure of sand. I just want either the sand manufacturers or the various sand-selling establishments in our area to wake up and realize there's a supply and demand issue here with the Safe Sand. (And a shout out to Strosnider's Hardware -- they don't have any safe sand but the manager actually thanked me for raising the issue). The Berkeley Parents' Network has helpful archives, as always, on the subject, but we're still playing in the maze of tree roots in our former-fish-pond-of-a-sandbox (hey, you have a magnet of a drowning hazard in your backyard, you make lemonade). Anyone know where to purchase safe sand? *Cross-posted at Surely You Nest