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

The Lawrence Journal-World reports Kansas Dental Association director Kevin Richardson insists fluoride reduces tooth decay and has been proven safe.

Wichita Republican Rep. Steve Brunk has introduced a bill in the House requiring the IQ notification, 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.

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