Almost every abrasive worth blasting with today is silica-free or low-silica, which is the direct answer to the health rule that pushed shops off sand. Garnet, glass bead, crushed glass, steel shot and grit, aluminum oxide, walnut shell, soda, and plastic media all carry little or no crystalline silica, and coal slag runs low enough to be classed as low-silica. Sand is the outlier, not the alternatives, so meeting the rule is mostly a matter of not using sand and knowing how to prove what you switched to.
The Hazard Is Crystalline Silica, Not Silica in General
The danger is respirable crystalline silica, the fine quartz dust that blasting sand throws into the air, and breathing it causes silicosis and lung disease. Silica sand is mostly crystalline quartz, so blasting it shatters that quartz into particles small enough to lodge deep in the lungs.
This is the distinction most media pages miss. Silica the element is in a lot of materials, but only the crystalline form is the regulated hazard. Glass bead and crushed glass are made of glass, which is amorphous silica, not crystalline, so they do not carry the quartz risk even though the word silica is in the description. Reading a media as safe or unsafe comes down to its crystalline silica content, not whether the word silica appears at all.
OSHA Caps Respirable Crystalline Silica at 50 Micrograms
Federal law sets a hard ceiling on exposure. OSHA limits respirable crystalline silica to a permissible exposure limit of 50 micrograms per cubic meter of air, averaged over an 8-hour day, with an action level of 25 micrograms that triggers monitoring. The construction standard is 29 CFR 1926.1153 and the general industry and maritime standard is 29 CFR 1910.1053.
Sand blasting throws so much quartz dust that holding exposure under that limit is impractical, which is why OSHA and NIOSH steer operations away from silica sand and toward the alternatives below. The full detail of the rule sits in [The OSHA Respirable Silica Rule for Blasting](#osha-silica-rule), and the history of the shift is in [Why Silica Sand Is Being Phased Out](#silica-sand-phased-out).
Silica-Free Media Carry No Crystalline Silica
Most of the media a shop already runs contain no crystalline silica at all, so switching off sand rarely means switching to something unfamiliar. The silica-free options are:
- Steel shot and steel grit, which are metallic and carry no silica
- Aluminum oxide, a manufactured mineral abrasive with no crystalline silica
- Garnet, a natural mineral that carries little to no free silica
- Glass bead and crushed glass, made of amorphous glass rather than crystalline quartz
- Walnut shell, soda, and plastic media, all organic or synthetic and silica-free
Each of these matches a different job, so the safe choice is also a working choice. The one that suits your part depends on the substrate and finish, which is the subject of Match Your Media to Your Substrate.
Low-Silica Media Like Coal Slag Run Under the Threshold
Coal slag, sold as Black Beauty, is the common low-silica option rather than a silica-free one. It is a by-product abrasive with a low free-silica content, low enough to be classified as a low-silica media, which is why it replaced sand as the cheap open-blasting abrasive across the Gulf Coast.
Low-silica is not zero, so a low-silica media still calls for dust control and monitoring under the OSHA rule. The point is that it starts far below sand, so the controls needed to stay compliant are realistic instead of impossible.
SSPC-AB 1 Classifies Abrasives by Their Silica Content
The abrasive industry has a standard for exactly this question. SSPC-AB 1, the specification for mineral and slag abrasives, sorts them into classes by crystalline silica content, so the class tells you how clean a media is on silica before you buy it. A media in the cleanest class holds the least crystalline silica, and the specification pairs that with performance grades for the profile the media produces.
For any specific media, the number to check is the free crystalline silica percentage on its Safety Data Sheet. That figure, not the product name, is what an inspector or a safety officer will ask for, and it is what separates a compliant abrasive from a liability.
A Silica-Free Medium Still Has to Fit the Job
Safety narrows the field, it does not pick the media. Choosing a silica-free abrasive that is wrong for the substrate trades a health problem for a quality problem, so the free-silica check runs alongside the job fit, not instead of it. Garnet and aluminum oxide profile hard metals, glass bead and soda finish softer parts, and coal slag handles cheap open blasting, and all of them clear the silica hurdle.
If you are moving a shop off sand, the path is short. Check the free crystalline silica percentage on the media's SDS, pick a silica-free or low-silica abrasive that matches the substrate and finish you need, and keep the dust controls the OSHA rule requires. Tell us the job and the surface, and we match you to a compliant media in stock that does the work.