Quote Originally Posted by Tom Hoskinson View Post
Sorry, Argument from authority, argumentum ad verecundiam is a logical fallacy, because the validity of a claim does not necessarily follow from the credibility of the source.

Also, If one wants to avoid contact with hydroxybenzenes (like hydroquinone, catechcol and pyrogallol) avoid barbeque's, smoke from wood fires and especially avoid tobacco smoke. Also, avoid Coffee. Include Dektol and any other developers that contain hydroquinone in your avoidance list.
This is quite true, however it is difficult to get volunteers to test the toxicity of tri hydroxy benzenes. Many sources do quote LD50 in rats and mice of all of these hydroxy compounds, and of them all, hydroquinone and metol are rather low causing kidney and liver damage but have a rather high LD50.

The tri hydroxy compounds kick toxiciity up a notch as Emeril would say, at least according to several sources. As you say, quoting them does not make them valid, but why take a chance and be an unwilling 'volunteer'. Use rubber gloves and use a mask when mixing powders.

BTW, the most toxic materials in charcoal fires and tobacco smoke by far are the benzopyrans as a class. They are major carcinogens and are also found on the surface of BBQd meats. In fact, you are getting more of the pyrans than you are of the HQ derivatives in smoke. HQ in smoke is almost an oxymoron as a reductant is not a major product of oxidation. You might want to check your sources on that.

Quinones OTOH are found in smoke and also in colored autumn leaves. Anthroquinones are a product of ageing of leaves when frost damages them. Quinhydrone was used for years as the colorant in green ink. It is a green byproduct of the oxidation of HQ in the absence of sulfite.

PE