Radio-frequency engineer Marvin Wessel has taken readings at more than 3,000 cellphone antenna sites across the country. Ryan Knutson
The antennas fueling the nation’s cellphone boom are challenging federal safety rules that were put in place when signals largely radiated from remote towers off-limits to the public.
Now, antennas are in more than 300,000 locations—rooftops, parks, stadiums—nearly double the number of 10 years ago, according to the industry trade group CTIA.
Federal rules require carriers to use barricades, signs and training to protect people from excessive radio-frequency radiation, the waves of electric and magnetic power that carry signals. The power isn’t considered harmful by the time it reaches the street, but it can be a risk for workers and residents standing directly in front of an antenna.
One in 10 sites violates the rules, according to six engineers who examined more than 5,000 sites during safety audits for carriers and local municipalities, underscoring a safety lapse in the network that makes cellphones hum, at a time when the health effects of antennas are being debated world-wide.
The FCC has issued just two citations to cell carriers since adopting the rules in 1996. The FCC says it lacks resources to monitor each antenna.
“It’s like having a speed limit and no police,” said Marvin Wessel, an engineer who has audited more than 3,000 sites and found one in 10 out of compliance.
On a sweltering June day in...