Emissions from a cell phone in the U.S., Europe and Canada must be measured and fall below published guidelines before it can be put up for sale. Specific absorption rate, or SAR, is "a way of measuring the quantity of radio frequency (RF) energy that is absorbed by the body," according to the CTIA.
The U.S. and Canada require a SAR rating below a maximum of 1.6 watts per kilogram while Europe will certify a phone with a SAR level below 2 watts per kilogram.
Here are the phones on the market in the U.S. with the 20 highest SAR levels. This does not mean that these phones are harmful - reasearch is plentiful but contradictory - so use your best judgement.
Tied at No. 18 is the BlackBerry Bold 9650 from Verizon with a SAR level of 1.43. (review)
To see the top 20 cell phones with the lowest radiation levels, check out this gallery.
At 4 is the Motorola i335 from Nextel with a 1.53 SAR level. (review)