There are 2 resources authored by UN Global Initiative to Fight Human Trafficking.
Designed for business managers and employees, this free online course helps understand what human trafficking is, how to identify where human trafficking might be a risk to their business, and identify action to address this risk.
EHTN / UN:GIFT, 2013
Guides business on how to avoid being implicated in human trafficking through the use of their products, services or facilities, as well as how to make a positive contribution.
ILO / IOM / UN:GIFT / Global Compact, 2010