Our reader Tamiko asks "It seems that every mineral makeup company has switched to micronized ingredients, making it somewhat fashionable. I would love to use this health conscientious company like Organic Makeup and have my family switch over to non-micronized mineral makeup, but they do not have a wide range of colors. Any advice"? At TreeHugger we don't give health advice. But we can help you construct a mental model to advise yourself. Start with the concept of "organic" minerals. A concentrated uranium ore right out of the bowels of the earth would be organic right? Bottom line: in mineral comparisons the term organic has little meaning. The term "micronized" refers to particle sizes in the micrometer range. We need to differentiate micro- from nano-sized mineral particles. The much smaller nano-scale particles exist in nature; but we are not generally exposed to them much as they quickly disperse or coalesce. If, for example, you had a jar of nano-sized mineral particles and inverted the jar at waist height, very little of it would make it to the floor below. If spilled in a small room this would be a sure way to expose your lungs and eyes. Not be a good idea, because initial research indicates that the smallest of nano-scale range particles may be able to cross the blood brain barrier. Micro-sized particles do not have this biological mobilty. They will not penetrate the skin and enter the blood stream.
Generally speaking, the purpose of face makeup is to present a smooth and pleasant feeling surface that reflects light in a desireable way. Not necessarily in a naturalistic way -- take face glitter as the unnatural extreme -- but in a way that is attention getting and pleasing to those whom the wearer wants to be noticed by. One quality that few wish to display is a greasy look. This is where the particle function comes in: presenting a smooth, evenly light dispersing, non-greasy surface.
Envision two very different shaped objects, both made of the same mineral material: one an angular surfaced, jagged particle, like a grain of sand in shape; the other a round smooth grain, like a ball bearing in shape. Keeping their respective shapes intact, we'll use our imagination to scale them down to micrometer size. Which shaped particles at micro scale would have the smoothest texture and which the best light reflecting characteristics? This is just the sort of question that a makeup formulators start with when blending materials. We can ony guess that its probably a combination of the two plus some bits of bat wing and eye of newt that make the products marketable.
For the final piece of our model we need to consider particle size distribution. Ever try to unclump some sugar that has hardened in the sugar bowl? Pretty soon you have some nice fine sugar in the bottom of the bowl and large clumps siting atop the fines. Its the same thing when you "micronize" a mineral for makeup. The bulk of it would be in a narrow band of micro-size range, while the rest would be either a "super micro" or "sub-micro" class of particle.
Take home messages:
* Organic does not equate necessarily to low hazard when it comes to minerals.
* Particle size distribution of inorganic minerals can be "wide," or be "narrow".
* Particle shape, size, density, and composition all figure into hazard potential.
* Nano-scale particles exist in nature and to varying extent in traditional manmade products.
* Regardless of average particle size, avoid putting on your skin any minerals which have exhibited high toxicity in an occupational exposure setting. You can evaluate this yourself by looking at material safety data sheets (MSDS) for the individual constituents of your makeup.
* If your sink and vanity area end up dusted with makeup, you are likely respiring these same particles. Even if toxicity is very low, dust can be an irritant. This is something to consider regardless of whether the ingredients are synthetic or "organic".
By Analogy: -- The hazard of tobacco in a cigarette is relatively constant, but exposure is zero until you light one. Health risk is cumulative: the more you light them, the higher the risk. In addition to all the take home points listed, risk of a potentially hazardous mineral dust depends upon how often you wear the makeup, how much of your face and neck you cover, how long you leave it on, how effectively you remove it, and so on.