The History of Henna and Hair
Henna in 1928, USA
(the beginning of the great depression)
Catherine Cartwright-Jones c 2004

In February, 1928, a physician wrote a banner article for Good Housekeeping magazine, titled "Shall I Dye my Hair?".  This article followed a number of toxic poisonings in New York City caused by hairdressers applying para-phenylenediamine dyes.  New York City passed an ammendment to the Sanitary code in 1926 to prohibit the use of noxious chemicals in hair dyes and cosmetics.  This law had little effect. 

The doctor stated flatly that the only safe and effective dye for hair was henna.