Name: Sam
Country: USA
Message: Hi Paula,

I spent a few years occasionally using a very brilliant alcohol soluble dye supplied to me by my employer for use in violin restoration called "Fast Orange". "Fast red" and "fast amber yellow" were also available to me. I think they were made by a company called 7K and they were referred to as aniline dyes.

I searched for info about this product as I became aware that many dyes were carcinogenic but I could find little information other than a possible reference to Sudan 1 (CI solvent yellow 14) being called "fast orange". I also see on your website that the diazo salts for naphthol dyes are referred to as "fast". 

Based on the limited information I have, do you have any idea what this dye could have been? Do you think that there could be any connection between the "fast" diazo salts and the dye that I was using?

I'm concerned that I was potentially using a pretty toxic dye. I was always very careful about the dust while using this dye, but I occasionally had some small amount of skin exposure to the varnish before I wised up and started using gloves. I also did not use a vent hood when adding the powdered dye to the varnish. I maybe went through 15-20 grams of the dry dye over a four year period.

Thank you so much for your attention to the safety issues with dyes. There is so little information available and some MSDS don't seem too comprehensive. I think eating lots of broccoli is my only ally sometimes.

This is an interesting question, but I'm afraid I have not gotten anywhere with locating your specific dyes. I haven't found anything about a dye or chemistry company called "7K", and the name "Fast Orange" would refer to ANY orange dye that the manufacturer wants to claim is resistant to fading due to light or water exposure.

"Aniline dyes" is a name that's applied to almost any synthetic dye. At one time most synthetic dyes were manufactured from the chemical aniline, but that has not been true for a long time, and yet the name persists. It's one of those words that sounds more scientific and meaningful than it actually is, the way that it is used. Some dyes described as aniline dyes are unsafe, but many other dyes equally well described this way are safe.

There are many, many dyes with the name "Fast Orange" or "Fast Red". For example, Classic Dyes, one of many large-scale dye suppliers, lists these dyes as being currently in stock under the name "Fast Orange" (with the generic Colour Index names, where available, in parentheses):

It is clear that the names "Fast Orange" and "Fast Red" tell you almost nothing about the dyes you used.

Some dyes that would be suitable for your purposes, based on what the seller says about them (I have no experience with them), might be the ColorFX Liquid Dye concentrates sold by a company called Wood Essence. What's interesting to me about them is that they are not dyes that bond to cellulose or lignin (the molecules wood is made of); instead, they are metal complex acid dyes that can react only with wool and other protein fibers. Since they do not themselves bond to wood fibers, they require a finish such as shellac or varnish to seal them in, to keep them from rubbing off on anyone or anything that touches the dyed wood. They can be dissolved in water, or, to avoid raising the grain of the wood, they can be dissolved in alcohol, like the dyes you have used. Note that this means that they cannot be solvent dyes, like the banned food coloring Sudan I, because substances that can be dissolved in water or alcohol generally cannot be dissolved in oily solvents. (Remember, oil and water don't mix.)

Since you don't know what kind of dyes these were, it is possible they were carcinogenic, but it's just as possible that they were not. Sudan I's carcinogenicity appears to be low enough to be significant primarily to those who have actually eaten it, as a food additive; if that were the dye in question, I suspect the amount of the risk of harm done by moderate exposures like yours would be very, very small.

High rates of bladder cancer were seen in employees of some dye manufacturers and other chemical industries who were exposed, generally more than twenty years ago, to large quantities of certain hazardous dyes and their precursors, the benzidine-based, toluidine-based, and o-dianisidine-based dyes. There are lists of these dyes in a 1980 US government document, "Health Hazard Alert--Benzidine-, o-Tolidine-, and o-Dianisidine- Based Dyes". Most of these dyes are in the category of direct dyes; interestingly, they were formerly found in all-purpose dyes, such as Rit All Purpose Tint and Dye, up through the 1970s, though they have since been removed from the formulas for safety. A book by Monona Rossol, "The Artist's Complete Health and Safety Guide", also gives lists of hazardous dyes. In the future, you can use an MSDS for dyes you use to look for signs that the dyes you are using are or could be based on one of these three chemicals (I will be glad to help in interpreting them).

As far as what can be done among exposed individuals to reduce the odds of future cases of cancer, the most important thing would be to avoid smoking and even second-hand smoke, because the effects of smoking combine badly with the effects of high exposures to carcinogenic chemicals, resulting (if I recall correctly) in risks that are higher than you would estimate by just adding up the separate risks. In fact, smoking alone is currently the biggest single cause of bladder cancer.

I would advise you not to worry particularly, since your exposure levels were low, you took some precautions, and since there is no particular reason to think that the dyes you were exposed to were carcinogenic. However, if you need an additional reason to avoid tobacco smoke, this could be one, and of course it would be wise to find out about the dyes that you use in the future, and to use gloves and avoid the possibility of breathing any dye powders, or any other powdered chemical. And, for what it's worth, we can all benefit from reducing our risks of cancer and other diseases by regularly eating broccoli and other vegetables and fruits.

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