What is DEA and why is it being removed from shampoos?

Diethanolamine (DEA), which is used as an emulsifier and foaming agent in shampoos, has been a suspect cancer-causing agent.  The presence of DEA in shampoos can also lead to the formation of nitrosamines, which are powerful carcinogens (cancer-causing substance). ALL FRAMESI COLOR LOVER and framesi BY products are DEA free.