Oral health advocates in Kansas are pushing back against an effort to require cities that put fluoride in their water to tell residents that fluoride lowers the IQ in children.

Wichita Representative Steve Brunk has introduced a bill in the House requiring the IQ notification. It’s based on a 2012 Harvard study that found a correlation between slower brain development and increased levels of fluoride in water.

That study focused on children in China, which unlike the U.S., has a high natural presence of fluoride in its water.

Kansas Dental Association director Kevin Robertson insists fluoride has been proven safe and reduces tooth decay.

Robertson says most anti-fluoride activists either believe fluoride causes cancer or that the government uses it as a mind-control agent.