GROWING TOBACCO has been a big business in the South since well before the United States was founded — and the rules governing child labor in the industry seem about as archaic.

Unlike in most of the rest of the economy, child labor on farms is lightly regulated, including in tobacco fields. The result, a Human Rights Watch report last week detailed, is sometimes-disgusting conditions for children and teenagers engaged in some particularly nasty agricultural labor.

In interviewing 141 juvenile workers who have experience on U.S. tobacco farms, investigators found that nearly three-fourths reported getting sick, many with symptoms of “green tobacco sickness,” a malady known to strike tobacco workers that is consistent with acute nicotine poisoning. These children, ages 7 to 17, described days-long headaches, dizziness, nausea and vomiting. Some had to cut workdays short due to illness. Others continued laboring. Many of them tried to cover up, wearing gloves and black trash bags. But high heat and long days made protective layers unbearable . Besides, wet days in humid tobacco-growing climates resulted in exposure to nicotine-laced moisture anyway.

Though the immediate symptoms of green tobacco sickness wear off, the long-term health effects aren’t clear. It seems clear that these children and teens absorbed significant amounts of nicotine, and there is evidence that the chemical stunts adolescent brain development.

Those who resist tighter agricultural child-labor standards often insist that more regulation would hurt time-honored traditions and family farming. But many of these child workers are day laborers, migrants or the children of migrants; some have U.S. citizenship, others don’t. They are not participating in an ancient family trade — they are simply being exploited — and tobacco farming is hardly a vocation beneficial to society.

The number of children toiling in the nation’s tobacco fields is not clear. But no one should be exposed to the conditions the report described. Tobacco-company policies vary in the labor standards they demand of their suppliers. Many, though, fall back on the argument that they follow or exceed the protections in U.S. law.

Yet federal rules are inadequate, putting few limits on the farm labor of children 12 and over. The Labor Department attempted to tighten its rules a few years ago, restricting children under 16 from working in tobacco farming. But after an outcry from rural interests, the Obama administration pulled the proposal . “To be clear,” a 2012 Labor Department statement read, “this regulation will not be pursued for the duration of the Obama administration.”

Now that Mr. Obama has been re-elected and no longer needs to court Southern swing states, his administration should reverse its pathetic retreat.