Name: mary 
Message: Do you know anyone who has done research on the toxicity of Procion Dyes.  I used them in the sixties.  My hands would stay colored for days, and I did not wear a mask when I mixed the powders.  Is there cadmium in their yellows?  Are there certain diseases that have been documented related to the use of dyes?

The dyes which are most likely to have caused health problems among employees of dye manufacturers in the US are derivatives of benzidine. However, there are no benzidine-based fiber reactive dyes. I've never seen any indication that any Procion type dye has ever contained or been made from benzidine. Benzidine-based dyes are no longer permitted for use in the US, but were included in all-purpose dyes (the kind of dye found in Rit brand dye) for home use during the 1970s and preceding decades. (See the government document "Benzidine and Dyes Metabolized to Benzidine" [PDF].)

None of the Procion MX dyes contain cadmium. Many of them, including the commonly used dyes blue MX-R, orange MX-2R, red MX-5B, and red MX-8B (fuchsia), contain no metals at all (see their chemical structures). Rubine MX-B and turquoise MX-G contain copper, at levels of perhaps 1 to 5% of the weight of the dye powder. Toxic metals do not appear to be a problem in Procion MX type dyes.

You can see MSDS pages for some Procion MX type dyes at PRO Chemical & Dye:
Yellow MX-8G (reactive yellow 86)
yellow MX-3R(A) (reactive orange 86)
orange MX-2R (reactive orange 4)
brown MX-GRN (reactive brown 23)
red MX-5B (reactive red 2)
red MX-8B (reactive red 11)
violet MX-2R (reactive violet 14) [often mislabeled as violet MX-G]
blue MX-R (reactive blue 4)
blue MX-G (reactive blue 163)
blue MX-2G (reactive blue 109)
turquoise MX-G (reactive blue 140)
...plus MSDS pages for many of their mixed dyes, but not for the rest of the unmixed single-hue Procion MX type dyes. Dharma Trading Company also provides their MSDS documents online; unlike ProChem and Jacquard, they do mention the small amount of copper in the Turquoise MX-G dye (which is the same dye regardless of which of these sources you use).

I have tried and failed to find reports indicating that Procion dyes have caused any problem other than allergies and asthma, among those chronically exposed to airborne dye powder. Fiber reactive dyes are known to cause quite significant respiratory-type allergies among some users, and this is widely documented. The best treatment for these allergies, once they develop, is strict avoidance of all powders and solutions of the dyes involved in the allergy. One well-known quilt artist was forced to give up using Procion MX dyes in favor of the quite similar Cibacron F dyes, to which she is not allergic. If you have not noticed obvious symptoms of difficulty in breathing when exposed to dyes, then this is not a worry for you at all, from your past history of dye exposure. It is not a subtle problem. It is, however, an excellent reason for everyone to be careful in all future exposures to dye powder, by wearing a properly fitting dust mask or respirator and avoiding contamination of the room used for dye mixing.

Procion MX dyes, like all dyes other than food colorings, have not been fully tested for safety in long-term high-level exposure. There is always a possibility that they or other untested substances might have a carcinogenic effect, though probably not among most users. This means that it is wise to avoid unnecessary exposure to the dyes, just for the sake of prudence. We should always wear gloves, use breathing protection until the dye powder is dissolved, avoid eating or smoking before washing hands, etc. One very useful property of fiber reactive dyes such as Procion MX is their rapid reaction with proteins in the dead skin cells that form a protective layer all over our skin. They are less apt than other dye classes to be absorbed into live skin cells, which makes them much less alarming than dyes which are known to be absorbed through even intact skin.

If you were careless with hazardous dyes in the sixties, such as the benzidine-based dyes that were included at that time in all-purpose dyes, what can you do about it now? The answer is not nothing. One important fact about carcinogens is that they tend to work together. Workers exposed to both benzidine and cigarette smoke have a much higher risk of bladder cancer than those exposed to benzidine alone. Avoid first-hand or second-hand exposure to cigarette smoke insofar as possible, eat vegetables and fruits since these are known to reduce some cancer risks, and mention any concerns you have to the physician who decides which screening tests should be part of your regular checkups. 

But don't worry. We don't have any particular reason to be concerned about any disease other than asthma in those overexposed to Procion MX dye powders, and you already know whether or not you have that problem; furthermore, that is not a crippling problem even if you have it, since it can be treated by future avoidance of these dyes.

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Updated January 29, 2009