Thank you for your reply. I have been searching the net and coming up empty but haven'given up.
Best,
J
No problem, I have been "trained" by a medical librarian who was sick to death of my requests, interestingly search strings can become very complex and in many cases a manual search of literature by a skilled librarian will turn up references the algorithm misses, there are a number of papers on the subject.
Probably a PQ developer then. Hydroquinone can't be the only developing agent in it.
The USA MSDS sheet reporting threshold:
MSDSs must be developed for hazardous chemicals used in the workplace, and must list the hazardous chemicals that are found in a product in
quantities of 1% or greater, or 0.1% or greater if the chemical is a carcinogen.
http://www.ehso.com/msds_regulations.php#DmQYHXv0iBmZI1LL.99
So if we use a P.Q. Universal formula:
Concentrated Stock Solution ID-62
Phenidone
1.25 g
Sodium Sulphite (anh) 125 g
Hydroquinone 30 g
Potasium Carbonate (anh) 95 g
Sodium Hydroxide 5.3 g
Potassium Bromide 5 g
Benzotriazole 1% soln 50 ml
Water to
1 litre
Which would not be reportable, by nearly a factor of 10.
It is not considered carcinogenic:
Carcinogenicity:
CAS# 92-43-3: Not listed by ACGIH, IARC, NTP, or CA Prop 65.
Of course we have no idea what the other developer/s in the formula are, if any, and I do not suggest it is Phenidone.