But scientists can't test every chemical. For example, growers bred celery to boost a natural pesticide to reduce insect damage. But at high levels, the pesticide was found to be harmful to humans. The celery never made it to market. Others benefit from the risk.
Growers yield larger crops due to pesticides.
Their desire for profit may make people less willing to put up with the risk. Officials oversell the safety. In the early 1990's, a pesticide, called alar, was well below safety levels in apples. But very high doses caused tumors in rodents. The media exaggerated the risk, scaring consumers.