community of dyers

Add another to the series of reasons to be cautious about direct dyes or the all-purpose dyes that contain them—which includes the dyes used in those gimmicky TIE DYE STRINGS that you can find in many crafts stores. Not only do they produce poor results: a few of these direct dyes can even be dangerous when used carelessly (as children are apt to do) or in large quantities (as in industry).

When I was browsing through an MSDS for "Tie dye cords", I found that they contain a copper-containing o-dianisidine-based blue dye. Copper does not worry me in the small quantities found in some dyes. What worries me is that o-dianisidine (pronounced oh-dye-an-ICE-i-deen). These cords are intended for use by children! Looking at a US government document, Health Hazard Alert--Benzidine-, o-Tolidine-, and o-Dianisidine- Based Dyes, it's clear that o-dianisidine is considered carcinogenic and a metabolite of dianisidine-containing dyes (that is, if the dye is accidentally absorbed, it will break down in the body into the cancer-causing chemical, o-dianisidine). Hmm. I could probably use that myself with precautions, but the careless way kids are likely to be using them is not at all safe.

We already knew that some direct dyes, and a few other dyes (NOT including fiber reactive dyes), are based on the toxic chemicals benzidine, o-tolidine, or o-dianisidine. Most of the benzidine-based dyes have been phased out in the US and a number of other countries. What we did not know was that o-dianisidine-based dyes are still included in dye products intended for use by children, children who are probably not even wearing gloves, let alone being watched to make sure they don't chew on their fingernails before they wash their hands.

It is known that dyes that are made from any of these chemicals may again produce these chemicals in the body after exposure to the dye. This can cause cancer, a few years down the line (or as many as thirty years later). It is a good idea to avoid them, or at least use safety precautions and keep them away from children who are too young to do so. What dyes are made from benzidine, o-tolidine, and o-dianisidine? Some direct dyes and all-purpose dyes.

There is a long list of benzidine-based carcinogenic dyes, almost all of which are direct dyes. Direct dyes are the cotton dyes found in all-purpose dye mixtures. (Rit is a brand of all-purpose dye, which too many Americans think is the only kind of dye there is.) Benzidine-based direct dyes have mostly been phased out, replaced by safer direct dyes. Many direct dyes probably are quite harmless; it's the others that we should be wary of.

"There is evidence that dogs, rats, and humans may metabolize some o-dianisidine- based dyes to the parent compound. As in the case of the o-tolidine-based dyes, a residual amount of the parent compound may be present in the dye."

Interestingly, the package pictured at Dick Blick is labeled "CONFORMS TO ASTM D4236 LABELING STANDARDS". A lot of people no doubt interpret that as meaning "NON-TOXIC", which is not correct. "Conforms to D-4236" on an art material label does NOT mean the product is "non-toxic."

So many people imagine that all-purpose dye must be safer than fiber-reactive dye, just because you can buy Rit dye in the grocery store. I do not know of any benzidine-based fiber reactive dye on the market, but benzidine-based direct dyes were a common ingredient in all-purpose dyes sold in the US up to and throughout the 1970s. They seem to have fallen into disfavor (though one would surely like to see a list of the dyes currently being used! unfortunately, the ingredients labels never give any hint). It looks like dianisidine-based dyes are still in common use, though.

If you use direct dyes or all-purpose dyes, you must assume, unless your dye supplier identifies which direct dyes they use, that some of them may even now contain carcinogenic dianisidine-based dyes, since we know now that some do. That means, keep them away from children, and follow all of our usual safety precautions closely: don't breathe the dye powder, don't let it get loose in your kitchen, wear reliable gloves, etc.

In general, direct dyes are inferior to fiber reactive dyes for most uses, but they are still very commonly used.