Researchers have identified almost 300 chemicals in everything from hair dye to pesticides that can increase levels of breast cancer-contributing hormones.

Ruthann Rudel, director of research for the Silent Spring Institute and co-author of the new study, told EHN that of those chemicals, 219 had not been previously identified as potential carcinogens. The findings come in a study out this week in Environmental Health Perspectives. 

Learn More: Breast Cancer: Hundreds of Chemicals Identified as Potential Risk Factors