(CNN) -- Cell phone users -- a group that, these days, means practically everybody -- are no doubt concerned about Tuesday's news that the World Health Organization (WHO) classifies cell phones as "possibly carcinogenic to humans."
The phones themselves aren't necessarily harmful. It's the radiation emitted by the phones -- and absorbed by the human body -- that troubles some doctors.
But when it comes to radiation levels, all phones aren't equal. Below are lists of the models available from major carriers that emit the highest and lowest levels of radiofrequency energy.
A quick explanation of the numbers: They refer to the "specific absorption rate" or SAR, a common benchmark that measures the rate of radiofrequency energy your body gets from the phone. The lower the number, the lower the radiation exposure. For a phone to be certified by the FCC and sold in the U.S., for example, its maximum SAR level must be less than 1.6 watts per kilogram.
But keep in mind that these are only ballpark figures. Your actual exposure will depend on how you use your phone, your carrier and network-specific conditions. For example, when your connection is weak, your cell phone needs to send out more radiation to reach the cellular tower.
And there's still no conclusive evidence that a phone with a higher SAR level poses a greater health risk -- or any health risk at all -- than a model that emits less radiation.
(These lists were compiled by the Environmental Working Group, a lobbying group that advocates on behalf of public health and the environment, based on data provided by the phone manufacturers. The data are up to date as of December, which means some newer models aren't listed. For the group's full list of phone models, click here.)
Lowest radiation levels:
1. LG Quantum (AT&T): 0.35 watts per kilogram
2. Casio EXILIM (Verizon Wireless): 0.53 W/kg
3. Pantech Breeze II (AT&T, AT&T GoPhone): 0.55 W/kg
4. Sanyo Katana II (Kajeet): 0.55 W/kg
5. Samsung Fascinate (Verizon Wireless): 0.57 W/kg
6. Samsung Mesmerize (CellularONE, U.S. Cellular): 0.57 W/kg
7. Samsung SGH-a197 (AT&T GoPhone): 0.59 W/kg
8. Samsung Contour (MetroPCS): 0.60 W/kg
9. Samsung Gravity T (T-Mobile): 0.62 W/kg
10. (tie) Motorola i890 (Sprint); Samsung SGH-T249 (T-Mobile): 0.63 W/kg
Highest radiation levels:
1. Motorola Bravo (AT&T): 1.59 W/kg
2. Motorola Droid 2 (Verizon Wireless): 1.58 W/kg
3. Palm Pixi (Sprint): 1.56 W/kg
4. Motorola Boost (Boost Mobile): 1.55 W/kg
5. Blackberry Bold (AT&T, T-Mobile): 1.55 W/kg
6. Motorola i335 (Sprint): 1.55 W/kg
7. HTC Magic (T-Mobile): 1.55 W/kg
8. Motorola W385 (Boost Mobile, U.S. Cellular, Verizon Wireless): 1.54 W/kg
9. Motorola Boost i290 (Boost Mobile): 1.54 W/kg
10. (tie) Motorola DEFY (T-Mobile); Motorola Quantico (U.S. Cellular, MetroPCS); Motorola Charm (T-Mobile): 1.53 W/kg
Some other high-profile phones fared somewhere in the middle on the rankings. The SAR level of the Apple iPhone 4 was 1.17 W/kg (for the AT&T model; the Verizon model wasn't listed). Exposure levels for the dozens of BlackBerry models varied widely.
CNN.com's Jacque Wilson contributed to this story.