Cell phone retailers in Berkeley are now required to post or hand out fliers warning customers of possible radiation exposure from the mobile devices.

The required warning is part of the so-called "right to know" ordinance voted unanimously by the city council in May 2015.

"I am excited," Berkeley City Councilman Max Anderson said of the ordinance that went into effect Monday. "It's been a long process.

Anderson spent years fighting the cell phone industry to establish Berkeley's cell phone "right to know" ordinance. The ordinance is the first law in the nation requiring cell phone retailers to warn customers about possible RF exposure.

"The people selling these products are not selling them for your good," Anderson said. "They're selling them for profit. They play fast and loose with regulations."

The fliers or signs required by cell phone retailers in Berkeley say in part: "If you carry or use your cell phone in a pants or shirts pocket or tucked in a bra when the phone is on and connected to a wireless network, you may exceed the federal guidelines for exposure to RF radiation."

Anderson said the goal is to get people thinking about keeping phones away from their body.

The CTIA represents the cell phone industry and is still fighting in court to stop the ordinance. The CTIA released the following statement: "The overwhelming scientific evidence refutes Berkeley's ill-informed and misleading mandatory warnings about cellphones, according to the FCC and other experts."