Though the science on the possible health effects of cell phone radiation is far from conclusive, several state and local governments are proposing legislation to address public concerns. And though no law has been implemented yet, it's clear the issue isn't going away.

How we got here Maine largely lead the way in early 2010 with a bill that would have required warning labels that cell phones may cause brain cancer. That legislation later died in a Maine House of Representatives committee, but other states and a few cities soon followed (Congress held a couple of committee hearings in 2009 but has taken no action). Then, almost a year ago, San Francisco really got the ball rolling when it passed a groundbreaking ordinance that required cell phone retailers to display the Specific Absorption Rate (SAR) for each phone model sold. That ordinance also was scrapped following opposition from the wireless industry, but San Francisco is trying again. And as the following list shows, lawmakers in city halls and statehouses across the country are joining the cause.

Some officials have simply called for more research to be done, but others are considering requiring health notices for cell phone packaging and mandating that stores inform customers that cell phones emit radio-frequency energy. CNET will continue to track developments as they unfold, and if we've omitted any cities or states from this report, please let us know in the comments section.

California What's being proposed California state Sen. Mark Leno (D-San Francisco) introduced SB 932 on February 18. As now amended by the Senate Committee on Environmental Quality, the bill would require the following notice on cell phone packaging and at the point of sale: "This device emits radio-frequency energy. Consult the user's manual for additional information on safe use." Additional language that said, "Do not hold or carry it directly against the body when connected to a network or you may be exposed to levels greater than the safety limit established by the Federal Communications Commission," was removed after the bill's introduction.

California state Sen. Mark Leno

Current status The California Senate committee approved the amended bill on May 9 by a 4-2 vote. It will now proceed to the full Senate for consideration. Leno also sponsored an unsuccessful bill last year, which required retailers to post a consumer safety warning and list the SAR for each model being sold.

Maine What's being proposed LD 1014, aka The Children's Wireless Protection Act, would mandate notices on cell phone packaging and at the point of sale that would warn users of the potential health hazards. The label on the packaging would read, "Warning: Federal health safety standards have yet to be established for nonthermal effects of cellular telephone radiation, which have been identified as reasons for health safety concerns, such as brain tumors." In stores, an expanded notice would advise users that cell phones should be used with care. It would include the following points.

Maine state Rep. Andrea Boland

Current status The current bill is sponsored by Maine state Rep. Andrea Boland (D-Sanford), who also introduced the unsuccessful 2010 bill. On March 31 of this year, LD 1014 was referred to Maine's House Committee on Energy, Utilities, and Technology. No further action has been taken and the legislative session ends June 15.

New Mexico What's being proposed New Mexico state Rep. Brian F. Egolf (D-Santa Fe) sponsored HM 32, which directs the state government to "study available literature and reports on the effects of cell phone radiation on human health." Also, by November 11, the Department of Health and the Department of the Environment must prepare a report with "recommendations on how to alleviate any dangerous effects that cell phone radiation has on human health."

New Mexico state Rep. Brian F. Egolf

Current status The House of Representatives passed the legislation by a 43-24 vote on March 13.

Oregon What's being proposed Sponsored by Sen. Chip Shields (D-Portland), SB 679 (PDF) would require retailers in the state to affix the following label to a phone and the phone's packaging. "Warning: This is a radio-frequency (RF), radiation-emitting device that has nonthermal biological effects for which no safety guidelines have yet been established. Controversy exists as to whether these effects are harmful to humans. Exposure to RF radiation may be reduced by limiting your use of this device and keeping it away from the head and body."

Current status Though there was a public hearing on April 11, a spokeswoman for Sen. Shields' office told CNET that the bill has been shelved for the remainder of the legislative session.

Pennsylvania state Rep. Vanessa Brown

Pennsylvania What's being proposed Like California's proposed legislation, HB 1408 also would mandate a label on cell phone packaging. As currently written, though, Pennsylvania's label specifically mentions possible health consequences. "This device emits electromagnetic radiation, exposure to which may cause brain cancer. Users, especially children and pregnant women, should keep this device away from the head and body."

Current status Introduced by Pennsylvania state Rep. Vanessa Brown (D-Philadelphia), the legislation now has 11 co-sponsors. On April 28 it was referred to the House Committee on Consumer Affairs. The 2011 session is scheduled to end June 30.

Arcata, Calif.

Councilman Shane Brinton, Aracata, Calif.

Current status Brinton said he is taking a "wait and see approach" to see how San Francisco proceeds with its amended "Right to Know" ordinance (see below).

Berkeley, Calif. What's being proposed On December 14 of last year, Councilman Max Anderson sent a letter (PDF) to fellow council members recommending that the specific absorption rate be disclosed for all cell phones sold in the city.

Councilman Max Anderson

Current status A representative for Anderson's office said no official legislation has yet been proposed and that Councilman Anderson is only discussing ideas.

Burlingame, Calif. What's being proposed Like Arcata and Berkeley, Burlingame has nothing on the table yet, but according to Councilman Michael Brownrigg, the council "has agreed in principle" to proceed with SAR-related legislation that could require retailers to "publish information for consumers that is already available, but in a more accessible format."

Councilman Michael Brownrigg

Current status Brownrigg said in an e-mail to CNET that he also is waiting for San Francisco to implement its final legislation before writing a proposal for Burlingame. "We may explore other avenues for alerting cell users to some simple techniques that reduce cell radiation exposure," he wrote.

Philadelphia What's being proposed On December 2, 2010, the city council passed a resolution (PDF) that authorized the Committee on Public Health and Human Services "to hold hearings on the potential health risks from cell phone radiation and the actions the city of Philadelphia can take to better educate all cell phone users, particularly children and teens, on ways to reduce radiation exposure by using headsets, speaker phones, and texting."

Councilwoman Blondell Reynolds Brown

Current status A representative for Councilwoman Blondell Reynolds Brown, who sponsored the resolution, said no further developments are expected before the city council begins its summer recess June 16.

San Francisco What's being proposed First passed last June, the "Right to know" ordinance (PDF) would have compelled retailers to post a consumer safety notice and list the SAR for each model of phone being sold. Also, retailers would have had to distribute consumer safety materials on request.

San Francisco Supervisor John Avalos

Current status Almost immediately, the CTIA, the wireless industry's lobbying arm, sued the city and moved its annual trade show to San Diego. After delaying implementation several times, city officials finally agreed to shelve the law late last month. An amended version of the ordinance that deletes the SAR requirement was introduced by Supervisor John Avalos late last month. As it now reads, the legislation would amend the San Francisco Environment Code "to require cell phone retailers to provide their customers with information regarding how to limit exposure to the radio-frequency energy emitted by cell phones in place of the mandatory disclosure of Specific Absorption Rate values for cell phones." Before it can be voted on by the full board, the bill will first be heard by the City Operations and Neighborhood services Committee. That could take place at the committee's June 27 meeting.