RALEIGH, N.C. (AP) — It could be a father hugging his children after a day’s work in the tobacco field, or pesticide residue on his clothing washed with family laundry. Maybe it was children playing in farming fields outside their homes.

A new study suggests all could be factors in high levels of pesticide exposure detected in children of migrant workers in eastern North Carolina, where an estimated 21,000 people in the heart of the state’s agriculture industry work in vast fields of tomatoes, cucumbers and other produce.

Educating workers and pushing for more enforcement of safety laws are central to protecting workers and their children from chemicals, experts say.

“We know that exposure to these pesticides creates all kinds of problems, we just don’t know exactly how much,” said Thomas A. Arcury, lead researcher for a study conducted by the Wake Forest University School of Medicine and published in the American Journal of Industrial Medicine.

The study analyzed urine samples from 60 children between the ages of 1 and 6 who lived with migrant farm workers in six North Carolina counties in 2004. The study looked for specific metabolites the body produces after being exposed to pesticides.

The study found the metabolite level in the North Carolina children was generally higher than the national averages of slightly older children, the only comparison data available, and either the same as or higher than levels found in similar studies in Washington state, California, Texas and Oregon.

Scientists weren’t sure if the levels were high enough to cause harm, the study said. Researchers concluded the results “are of concern,” because exposure to pesticides has been linked to health issues ranging from nausea to cancer, problems in lung and brain development, and even death.

“This information is helpful, but it’s only a snapshot at a particular time,” said Allan Noe, spokesman for CropLife America, a trade group of pesticide manufacturers.

But advocates said the study would be helpful in pressuring officials to focus on enforcement of safety rules.

With the recent surge in immigration — North Carolina saw its undocumented immigrant population grow 43 percent to 300,000 from 2000 to 2004, according to the Pew Hispanic Center — advocates say the need to educate workers has increased.

“Most of them come from Mexico, but little groups of them come from all over the world, and a lot of them travel with their families,” said Omar Lainez, community education coordinator with Legal Aid North Carolina’s Farm Unit.

The nonprofit group visits migrant and seasonal farmworkers at camps, sometimes set up near crop fields, to teach them about pesticide safety and the legal remedies available, such as the right to ask employers for proper safety equipment and what pesticides are used, Lainez said.

“The workers normally don’t say anything, because they’re afraid,” he said, adding that he has seen empty pesticide containers near or inside homes.

Concern has heightened since three workers for Ag-Mart, which grows tomatoes in eastern North Carolina, had babies with serious birth defects. A state report released in May said pesticide exposure may have caused the defects, but stopped short of making a conclusive link.