Pesticides are sprayed everywhere and end up in our food. Just as Agent Orange was found to be carcinogenic from the Vietnam War era, more recently Round Up (glyphosate) was found to be carcinogenic. There are so many chemicals that farmers and homeowners (runoff) use. It's just the tip of the iceberg. 

PubMed
Exposure to glyphosate-based herbicides and risk for non-Hodgkin lymphoma: A meta-analysis and supporting evidence - PubMed
Glyphosate is the most widely used broad-spectrum systemic herbicide in the world. Recent evaluations of the carcinogenic potential of glyphosate-b...