The city council in Berkeley, California voted on Tuesday night to pass a cellphone "right to know" law requiring health warnings with the purchase of a cellphone.

The proposal was passed by a vote of 9-0 and when it goes into effect this summer it will be the first safety ordinance of its kind in the country.  Cellphone retailers will be required to include a city-prepared notice along with the purchase of any new cellphone, informing consumers of the minimum separation distance a cellphone should be held from the body.

The Federal Communication Commission recommends keeping your phone 5 to 25 millimeters away, depending on the model, to limit radio frequency exposure to safe levels.

"If you carry or use your phone in a pants or shirt pocket or tucked into a bra when the phone is ON and connected to a wireless network, you may exceed the federal guidelines for exposure to RF [radio frequency] radiation," the Berkeley safety notice reads. "This potential risk is greater for children. Refer to the instructions in your phone or user manual for information about how to use your phone safely."

The new law is set to take effect in July, but may face legal challenges delaying when it will go into effect.  The Cellular Telephone Industries Association, for example, has stated that the law violates the First Amendment because it would force wireless retailers to disseminate speech that it may not agree with.

In a letter to the council members Tuesday, Gerard Keegan with the CITA said, "The forced speech is misleading and alarmist because it would cause consumers to take away the message that cell phones are dangerous and can cause breast, testicular, or other cancers."

While research continues, some health activists are already campaigning for more stringent cellphone safety regulations.  Lawmakers in at least six states have already considered warnings to address concerns surrounding cellphone radiation.

In 2010, San Francisco approved regulations mandating cellphone retailers display the Specific Absorption Rate, or the amount of radio frequency energy absorbed by the body, for each phone sold.  However, it was challenged in court by the Cellular Telephone Industries Association, claiming the law would confuse consumers by implying that lower radiation levels are safer.  This argument led to the ordinance being thrown out.

The Berkeley proposal seeks to address growing concerns even as cellphones cement themselves in our every day lives while many people still remain unaware of basic safety recommendations.

In a survey on April 30 funded by the California Brain Tumor Association, researchers found that 70 percent of Berkeley adults did not know about the FCC's minimum separation distance and 82 percent said they would like information about how far phones should be kept from the body.