I believe there is very through discussion at the LF forum about this. The article is nothing more than another pitch for unsharp masking by Howard Bond. There are many things in the article that are if not inaccurate they are at least biased. For one, he used PMK with tmx 100, a film that most everybody that uses PMK knows it does not stain as well as most other developer.
As to the toxicity, Bond cites the book by Susan Shaw, a book that is full of errors and is nothing more than a compilation of MSDSs or toxicity data, without any regard to the use and method of use of the chemicals and certainly without any intelligent analysis.
To judge toxicity you need to look at 3 important factors. Chemical concentration, length of time exposed to the chemical and route of entry into the system.
Lets start with the concentration. I dont recall exactly the LD50 of pyro, but I remember is somewhere around 250 mg/kg. With PMK you start with a 10% stock solution, so if we fudge a little and set the density of this solution to 1, you have in the stock solution 100,000 mg/kg. To use it you then dissolve the stock solution a 100 fold, leaving you with approximately 1000 mg/kg. Now, lets say the average person who uses this developer is 176 pounds or 80 Kg. If you multiply 80 x 250 mg/kg, you find that a dose that would be harmful to you would be around 20,000 mg/kg. IOW 20 times more than what you use for developing and twice as much than what is contained in the stock solution.
Lets move on to the length of exposure time. The LD50 doses are arrived by feeding the subject big amounts of the chemical on a daily basis until 50% of the subjects die. This can take days, weeks or months, depending on the chemical. Unless you plan to add 20 grams of pyro to your diet on a daily basis, the chances that you will be exposed to pyro long enough to cause you harm are close to infinitesimal.
Now, finally we move on to the route of entry. Lets say you decide to develop with PMK and you put your hands in the developer without gloves. Lets further assume that you absorb all of the pyro through your skin (clearly impossible, the pyro would be gone and you would not have a developing action). At this time you have been exposed to a dose that is 20 times lower than the one determined to be harmful and if you stop developing, you have only been exposed for a small amount of time.
Of course, if you develop everyday, take no precautions and eat, drink and smoke in your darkroom, well then yes your chances of getting sick are greater, but it might not be only because of the pyro.
Now, the sentence about the pesticide. First, pyro is used in hair dye, I dont see people dropping off like flies after getting their hair tinted. Second, just because it is similar, does not mean it is the same, nor that it has the same effects on the body. Funny thing is, D76 has a developing compound that is very similar to pyro, yet we dont see Bond making any objections to it.
The Parkinson's statement is so ridiculous it chaps my hide. For one, Weston also used amidol, another benzene derivative, for another, there are millions of people who get Parkinson's without ever coming within 50 miles of pyro. His statement that people say "well nothing has happen to me" as proof of safety should not even be written, since he only offers the case of one person who happened to use pyro and get Parkinson's. How stupid is this?
Bottom line John, the article is a self serving ad for his unsharp mask and his workshops, he wrote about things about which he has no knowledge based on the flawed and alarmist research of a woman whose only merit was to read MSDS sheets and write about them on a terrible book.
It is unfortunate that people like him write these things and they become part of the "truths" of photography, just because Bond said it.
I cannot guarantee you 100% that nothing will happen to you, but with a little bit of care, good laboratory practices and a little bit of common sense I can guarantee you that if a drop falls on your arm, your gonads are not going to shrivel. All this based on careful analysis of the evidence, not on some hear say, or faulty information from from a woman that was too lazy to think.