People who use smokeless tobacco products have higher levels of nicotine concentrations in their systems, as well as more tobacco compounds linked to increased cancer risk, compared with cigarettes smokers, a new study finds.

The study of almost 24,000 adults is published in Cancer Epidemiology, Biomarkers & Prevention. It was conducted by researchers from the Food and Drug Administration and the Centers for Disease Control and Prevention, according to Time.

The study found adults who used only smokeless tobacco, such as snus or chewing tobacco, had higher levels of tobacco-specific nitrosamines, which are compounds associated with an increased risk of cancer. Study participants provided urine or blood samples for measurement from 1999 to 2012, the article notes.

“Our results have shown that smokeless tobacco users have high levels of known harmful and addictive constituents and that in some cases these levels are higher than those observed among cigarette smokers. This finding is a cause of considerable concern for individual and public health,” the study authors wrote.

Almost 10 percent of male high school students reported they chewed tobacco, snuff or dip in 2013, the researchers noted.

This spring, Swedish Match asked the Food and Drug Administration to certify its General brand of snus as “modified risk.” The company wants to be able to claim snus products are addictive but much less risky than smoking. Swedish Match wants to be able to remove one of the required health warning labels about oral cancer. The company has sold snus in the United States since 2007.