Thanks very much, John! You really had me worried for a minute there. I was thinking -- could I have lost my mind and actually written that stuff about mercury? Steve is the greatest co-author ever, but -- let's put it this way: I accept full responsibility for every syllable in the Film Developing Cookbook. I don't accept any responsibility for anything Steve has written on his own. With regard to the general issue of carcinogenicity, as we all know, there would be few women left on Earth if the photographic chemicals commonly used in hair dyes were all that carcinogenic. Somehow, in over a century of use, there seems to be little decisive linkage. With regard to pyro, the chemical, throughout most of the 20th century, was used so many orders of magnitude less than HQ that the medical evidence (and the need to acquire it) simply isn't there. I know Steve believes that careless pyro use was responsible for health problems with the Weston men; that hasn't been medically established; it's anecdotal opinion. But there is a lot of anecdotal opinion out there. A lot. Since we will never know just how dangerous pyro really is (because it will never be used enough to warrant the research), it seems to me prudent to treat it with extra care. What's the harm in spending a few more minutes in the darkroom making sure you minimize your exposure to chemicals? The darkroom is a serious place; it's not a playpen.
Originally Posted by john_s