Oct. 30, 2009 -- Walmart and the Kroger supermarket chain have severed ties with one of the country's major blueberry growers after an ABC News investigation found children, including one as young as five-years-old, working in its fields.

The children were discovered at the Adkin Blue Ribbon Packing Company, in South Haven, Michigan, this summer by graduate school students working with ABC News as fellows with the Carnegie Corporation.

The full report on the investigation airs tonight on Nightline.

A five-year-old girl, named Suli, was seen lugging two heavy buckets of blueberries picked by her parents and brothers, aged seven and eight.

An 11-year-old boy in the Adkin fields told the Carnegie fellows he had been picking blueberries since the age of eight.

CLICK HERE TO SEE MORE CHILDREN FOUND WORKING IN THE FIELDS.

The owner of the company, Randy Adkin, was once featured on a Walmart billboard advertising his "locally produced and locally sold" blueberries.

"Walmart will not tolerate the use of child labor," said a spokesperson who said the retailer was unaware of the children at the Adkin facility until contacted by ABC News.

"We will not purchase any additional product from Adkin Blue ribbon Packing Company pending the outcome of an investigation by our ethical sourcing team," the Walmart spokesperson said.

Separately, the Department of Labor cited Adkin this week for violating federal child labor laws. Inspectors reported they found a six-year-old picking blueberries in Adkin's fields this summer.

As part of the ABC News investigation, the four Carnegie fellows spent weeks in fruit and vegetable fields in Michigan, New Jersey and North Carolina.

"What it really comes down to is small fingers picking the smaller fruits and vegetables," said Joel Stonington, a recent graduate of the Columbia University Graduate School of Journalism.

In Michigan, a legal aid attorney who works with migrant families, Teresa Hendricks, said the enforcement of the federal child labor law is "very lax."

On Friday, the United Fresh Produce Association sent a letter to its members referencing the "alarming" ABC News investigation, urging members to "redouble your efforts to ensure that no young children are ever working illegally on our farms."

The Law & Child Workers

The law prohibits, with only a few rare exceptions, the use of any child under the age of 12 on large agricultural operations.

Yet, as migrant families try to scrap by on meager earnings, they often put their children to work with the tacit acquiescence of growers and their foremen.

CLICK HERE TO SEE MORE CHILDREN FOUND WORKING IN THE FIELDS.

"Everybody knows that's the economic reality for the families," said Hendricks, "and so it's something that happens and people just put their head in the sand and know that it happens, a nod and a wink and we look the other way."

Adkin, the Michigan grower, told ABC News he "would fire" anyone who allowed children to work in his fields. Indeed, Carnegie fellows Angela Boyd, from Harvard University's Kennedy School of Government, and Kieran Meadows, from the City University of New York's Graduate School of Journalism, saw a sign in Adkin's fields one day saying children were prohibited. Read the statement Adkin sent to ABC News by clicking here.

The sign was lying in the back of a truck the next day when the Carnegie fellows videotaped the children in the fields.

Human rights groups say the use of child labor is widespread in fruit and vegetable fields across the country.

"Americans think of child labor as a problem elsewhere, but in fact we have that problem in our own backyard," said Zama Coursen-Neff of Human Rights Watch, which is conducting its own investigation of child labor practices in the U.S.

"There is child labor in agriculture in almost every state in the United States," she told ABC News.

In North Carolina, Carnegie fellows Stonington and Linsay Rousseau Burnett, of the U.C. Berkeley Graduate School of Journalism, recorded children working in tomato fields in the western part of the state.

The nurse with a migrant health clinic program, Josie Ellis, told the fellows she is concerned for the health of the young children given the widespread use of pesticides in the fields.

"A lot of the chemicals that the kids are around cause respiratory illness, neurologic impairments, contact dermatitis, really severe rashes on their bodies," Ellis said.

The nurse said her complaints to the U.S. Department of Labor office, several hours away in Raleigh, rarely resulted in any action.

"They just don't seem to really care," she said.

Promised Crackdown on Child Labor Violations

The Obama administration's Secretary of Labor, Hilda Solis, promised a crackdown on child labor violations after taking office.

This summer, labor inspectors cited blueberry growers in North Carolina, Arkansas and New Jersey for using children in their fields, with fines averaging $1,100 per child.

While advocates for children welcomed the enforcement efforts, many say the fines levied by the Department of Labor, are so slight they're little more than a slap on the wrist.

"I think it's shameful that our nation tolerates child labor," said Ellis, the North Carolina nurse.

Human Rights Watch investigators say the law needs to be broadened so that it is illegal for children who are 12 and 13 to work in agricultural settings.

"We don't let them work in factories," said Coursen-Neff, "only in agriculture are kids allowed to trade in their health and education."

The executive director of the North American Blueberry Council, Mark Villata, said the industry "does not condone the use of child labor."

But, said Villata, "we cannot control the practices of every one of the more than 2,000 blueberry growers in the United States." He said he believes the ABC News report "represents only a tiny segment of our industry."

2009 Carnegie Fellows

Angela Boyd (top left), Joel Stonington (top right), Linsay Rousseau Burnett (bottom left) and Kieran Meadows (bottom right) were 2009 Carnegie Fellows with the ABC News' Brian Ross Investigative Unit. The 10-week summer fellowship was sponsored by the Carnegie Corporation.

Angela Boyd is a graduate student at Harvard University's Kennedy School of Government.

Joel Stonington is a recent graduate of Columbia University's Graduate School of Journalism.

Linsay Rousseau Burnett is a graduate student at U.C. Berkeley's Graduate School of Journalism.

Kieran Meadows is a graduate student at CUNY's Graduate School of Journalism.

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