California issued new guidelines to decrease exposure to cell phone radiation.

The guidelines are likely to be controversial, since scientific consensus has not been reached on the health impacts of cell phone usage, even as virtually all adult Americans are using a mobile device, and children begin use earlier than ever.

Among the key tips to reduce exposure: keeping the phone away from the body as much as possible when not in use, and also keeping it an arm’s length or more away from the bed at night, according to the California Department of Public Health.

“Although the science is still evolving, there are concerns among some public health professionals and members of the public regarding long-term, high-use exposure to the energy emitted by cell phones,” said Karen Smith, the director of the agency, and the state’s public health officer.

“Children’s brains develop through the teenage years and may be more affected by cell phone use,” she added.

Among the recommendations:

  • Keeping the phone away from body, and not in pockets.
  • Moving the device at least an arm’s length away while sleeping.
  • Reducing use when cell signal is weak.
  • Cutting back on use of mobile devices to stream audio and video, and downloading and uploading large files.
  • Removing headsets when off a call.
  • Avoiding products claiming to block cell radiation – since they may actually increase exposure.
  • Refrain from using when in a fast-moving car or train.

Cell phones “talk” to cell phone towers using radiofrequency signals, which is a form of electromagnetic radiation. (Cell phones also the signals when using Wi-Fi and Bluetooth, but at lower levels). Other sources of the radiation include the cell-phone towers themselves, TV and radio transmitters and certain appliances like microwave ovens.

The California health authorities cite the linkage of brain cancer and tumors of acoustic nerve and salivary gland to cell phone usage, as well as lower and less mobile sperm, headaches and memory and behavior problems. However, those effects have been acutely debated. For instance, a massive study of 13,000 cell phone users over a decade conducted by the World Health Organization ultimately concluded in 2010 that there was no increased risk for brain tumors - although "suggestions" in the data linking heavy usage to gliomas (a deadly tumor) made it "possibly carcinogenic to humans." But in 2013, Tel Aviv University scientists found high oxidative stress in the saliva of heavy cell phone users – indicating a possible connection between tumors and tuning in.

The California release follows a successful lawsuit and public pressure from one of the most prominent critics of cell phone safety at the University of California Berkeley.

Joel Moskowitz, director of the Center for Family and Community Health at UC Berkeley School of Public Health, won a lawsuit against the California Department of Public Health in March. Moskowitz sued for access to the original document prepared in 2009 but never released – and was given 27 drafts of the document that had been continually updated. Moskowitz said in a recent posting on his site “Electromagnetic Radiation Safety” that the new California warning is similar to one issued by its Connecticut counterparts two years ago.