Children are not allowed to buy cigarettes in the United States — but they are allowed to work in tobacco fields. In North Carolina, Kentucky, Tennessee and Virginia, a survey has found that they're showing symptoms of nicotine poisoning. Restrictions on child labor in the US are different for agriculture than for other industries. On large farms, kids as young as 12 can work legally for unlimited hours when they're not going to school. Last year, Human Rights Watch surveyed 141 child tobacco workers, aged 7 to 17. Zama Coursen-Neff is director of the Children's Rights Division of Human Rights Watch and co-author of a report on the survey's findings.