(CNSNews.com) - As of January 1, all large retailers and manufacturers doing business in the State of California must post notices on their Web sites, explaining what, if anything, they are doing to ensure that none of their suppliers engages in slavery, forced labor or human trafficking.

The "California Supply Chain Transparency Act", signed into law in September 2010 by then-Gov. Arnold Schwarzenegger (R), took effect last month. Backed by human rights advocates, the law applies to companies with more than $100 million in annual gross receipts doing business in California -- regardless of whether the company is located in the state.

One U.S. lawmaker has proposed similar legislation at the federal level, saying it would motivate businesses to make sure humane practices are being observed throughout their supply chains.

As required by law, many large companies doing business in California are now posting notices on their Web sites, explaining how they will ensure that their suppliers, both national and international, are not tainted by human trafficking -- something that is difficult to do. In fact, as the law itself states, "these crimes are often hidden from view and are difficult to uncover and track."

The goal is to discourage consumers from patronizing companies that don't monitor their supply chains for child and forced labor.

The law (SB 657) says it is California policy to “ensure large retailers and manufacturers provide consumers with information regarding their efforts to eradicate slavery and human trafficking from their supply chains” so consumers can make educated choices “to purchase goods produced by companies that responsibly manage their supply chains, and, thereby, to improve the lives of victims of slavery and human trafficking."

A random check shows that Georgia-Pacific and Home Depot are two of the many companies now posting “transparency” notices on their Web sites, in which they describe their "risk-based approach" to monitoring their suppliers.

"Georgia-Pacific's commitment to ensuring that its supply chain is maintained in a socially responsible way includes, among other things, an expectation that suppliers not use forced labor in any of its forms, including human trafficking and slavery, to produce the products they provide to Georgia-Pacific," the company's disclosure notice says.

Georgia-Pacific says it has a "three-stage assessment process" that begins with a request for its suppliers to provide detailed information. If the response triggers concern, the supplier is moved to "stage two" -- a conference call or other meeting with the supplier.  Stage three may include an unannounced visit to the supplier, and depending on what is discovered, the supplier relationship may be terminated.

Home Depot, on the other hand, says it has staff around the world -- and "utilizes a number of third party social responsibility firms” to monitor and prevent humans rights abuses in its supply chain.

In addition to monitoring their supply chains, many companies also are training their employees on how to identify and respond to forced-labor issues.

How big a problem is this? Last October, the Bureau of International Labor Affairs -- part of the U.S. Labor Department -- listed a total of 130 goods from 71 countries that are believed to be produced by forced labor or child labor in violation of international standards.

The countries span every region of the world and are at different stages of development. "More goods were found to be made with child labor (children under age 15) than forced labor," the report says.

The list of countries includes China, India, Afghanistan, Pakistan, the Philippines, and various African, Central American and South American nations.

At the federal level, Rep. Carolyn Maloney (D-N.Y.) has introduced legislation that “encourages” companies with $100 million in gross receipts to post on their websites what policies they have in place to ensure their supply chains are free of slavery and human trafficking and to report this information to the Office To Monitor and Combat Trafficking in Persons at the State Department. 

“It will increase transparency, allow consumers to make informed decisions, and motivate businesses to ensure humane practices throughout their supply chains,” Maloney said. “We don’t tell companies what to do, we ask them to tell us what they are doing.”