This is a difficult question to answer. The FCC states that cell towers are not a health risk when operated in the limits prescribed by the FCC. The Telecommunications Act of 1996 prohibits local zoning boards from even reviewing health as an issue when cell towers are submitted for approval.
There are many studies cited by the industry purporting to show that no health risks exist. However, some critics suggest that the majority of studies have been done on the effects of using the cell phone itself, not on the proximity to towers. There are studies that have been commenced that study the issue of long term exposure to cell towers, but the results will not be ready for quite some time. There are countless web pages that deal with both sides of this issue. Do a Google search on cell tower radiation or cell tower health and you will easily find them