I came across this information..dunno what to think!
Skin-whitening soaps are for more than a half century were produced as Anti-Septic Soaps with ingredients like ammoniated mercury, potassium mercuric iodide, and other toxic mercuric compounds,carboxylic, and its hydroquinone derivatives.These whitening soaps were household trend consumables and were estimated that more that US$100 billion worth of these whitening (aka: antiseptic) soaps were sold in African continent alone in the past 50 years.
In the early Fifties (1950s) when the knowledge of ochronosis (Deposition & accumulationof dark brown pigment in bone cartilage, bone joint capsules and other tissues, usually resulted of alkaptonuria). Alkaptonuria is congenital absence (in off-springs of) in users of mecuric, carboxylic, phenol hydroquinone based whitening/antiseptic soaps) of homogentisic acid oxidase, an enzyme that breaks down tyrosine and phenylalanine.
Accumulation of homogentisic acid in homozygotes causes brown pigmentation of skin and eyes and damage to joints other organs, urine blackens on standing; were known based on extensive medical studies on the prevalent epidemical medical conditions of whitening /antiseptic soap users.
The large multi-nationals then (by 1960s) discontinued the uses of mercuric,carboxylic and phenol hydroquinone in their branded soaps, but the smaller soap manufacturers (mainly East Indian firms) in these countries grapped the opportunity of the market vaccum-created to supply the still existing excessive demand,which saw the introduction of "Roberts Brand","Bukilsal" and "Robert Medicated" antiseptic soap which main purposes are for skin-whitening effect; emerged as intra-africa national soap brands.
A toxic mercuric antiseptic family soap brand "Crystal White" {from Robert'sGroup} circa. 1950s