I wrote to The Color Run organization and asked precisely what was the color thrown on the runners. Within a couple of hours I got a courteous and very detailed reply email telling me precisely what the color is.
"The color is a corn starch base and is dyed with food grade dyes. It is even Gluten free.
Here is a list of the ingredients in our color:
Blue - FD and C Blue 1 Lake Low, Melojel Starch.
Green - FD and C Blue 1 Lake Low, FD and C Yellow Lake 36-42 PCT, Melojel Starch.
Pink - FD and C Red 40 Lake 36-42PCT, Melojel Starch.
Yellow - FD and C Yellow 5 lake 36-42 PC, Melojel Starch."
So, the main ingredient is Melojel Starch, which is a high quality, food grade, corn starch. It has a very silky texture which would make it ideal for the base of these colors which they essentially throw at the runners.
This is what its Material Safety Data Sheet (MSDS) says, "While cornstarch is commonly used in cooking, you should avoid eating or drinking large quantities of cornstarch. Do not get cornstarch dust in your eyes. Avoid inhaling cornstarch dust when using. If one of these exposures happens, provide treatment as indicated. If irritation continues, contact your physician."
I took a look at the Food Grade food dyes which they use, and are listed above.
The Blue is the most interesting from a toxicology standpoint, in that it's been banned in several European countries over the years despite getting the okay from EU health officials.
All the food dyes used state the following on their MSDS, "Dust inhalation may cause respiratory irritation. Solid particles on the eye (powder/dust) may cause pain and be accompanied by irritation. Repeated or prolonged skin contact may cause irritation."
"Caution must be exercised by the prudent use of protective equipment and handling procedures to minimize exposure."
Okay, I'm aware that MSDS sheets are notorious for overstating problems, but I don't think it's the case here.
At the same time, it would appear the The Color Run does just the opposite. In their FAQ, it states, "The Color Run explosions are basically food grade cornstarch and are 100% natural and SAFE. As with any substance, you want to keep it out of your eyes and our “certified” color throwers make sure to aim low as you pass by."
Talk about malarkey.
While the color is "food grade" and mostly made of corn starch, that's not the only ingredient in the colors. There is also the food dye.
The corn starch may be 100% natural, but the food dye isn't.
Just because something is 100% natural, whatever that actually means, that doesn't translate into it being "SAFE." Benzene is a naturally occurring substance, and exposure to it can cause cancer.
If you're allergic to these ingredients, enough of it on your skin, in your eyes, etc., could bring on very serious anaphylaxic shock. That can kill some people. And the big problem is that many who are seriously allergic to the color, don't know it. That raises the stakes significantly.
If the color throwers are aiming low, how come almost every photo of contestants on the Color Run website show them covered all over their faces with the color, as well as most of the rest of their body?
Bottom line, I wouldn't consider going in one of their races, or even photographing it.
I'm not even going to talk about the fact that they are a profit making company, making no bones about that, I should add, and apparently very little money from what they make at each race actually goes to charity.
I shot a colour run here in Perth.. my glass (and lungs) are fine...
however - there was a strong wind that day and I didn't have a cover so I spent most of my time being "up wind" and not getting into the thick of it. The 'pros' just had little plastic bag things over their gear, they seemed more worried about their clothes getting covered in colour
I suspect that most of the cornstarch actually gets trapped by mucous before it reaches your lungs, being very fine and highly absorbent, what might get through would be no more damaging than walking through a field of corn (or the equivalent).
It's not surprising that they have now excluded insurance coverage on damage from Color Run and similar events. I suspect pros that photograph Color Run have learned to use rented gear rather than personal gear.