OldGuy43 wrote: WARNING!: I bought a bag of play sand for the same purpose just the other day and was amazed to find a notice similar to this on the bag:
How did the state of California get so much smarter than the rest of us?
Because `actual' risk isn't what they're interested in. They place labels like this on many products and it is all `relative'. Play sand/beach sand/almost all sand is composed of silica. Finely ground - powdered sand/or calcined amorphous DE can, over the course of years (occupational exposure, primarily) lead to Silicosis. The easiest way to allay ANY concern about ANY sand is to simply rinse it (fine particles into ground). The greatest exposure to Silica `dust' by most anyone not in the industry is on hot, dry windy afternoons when, depending on the composition of the local soil, one can huff a considerable amount of wind borne (though far, far below a clinically significant amount) crystalline silica; gravel roads, anyone?
A study on workers mining/processing diatomaceous earth to give some sense of `actual' risk among those who are exposed on a daily basis to Crystalline Silica over a period of years (amorphous is what most chickeneers use/Calcined (crystalline) is what
really kills insects quickly, can lead to Silicosis and keeps pool filters from clogging up):
Workers in this study were employed in one diatomaceous earth mining and processing facility in Lompoc, California; operations at the facility included extraction of the mineral from open-pit mines, crushing of the ore, and heating of the crushed ore at high temperatures (calcination). When extracted, the mineral exists primarily as amorphous (noncrystalline) silica; after heating, the product typically consists of 10 to 60% crystalline silica, primarily in the form of cristobalite.
The percentages of respirable dust estimated to be crystalline silica for jobs involving exposures to natural, calcined, and flux-calcined diatomite were 3%, 20% and 60%, respectively. If the exposure was to a mix of these diatomite types, a weighted percentage corresponding to the estimated mix was used.
http://ajrccm.atsjournals.org/cgi/content/full/158/3/807
Though, anyone wanting to worry about going to the beach, go ahead and worry.
