Responding to some teachers’ concerns about health risks, the Portland School District hired a company to test the level of radio frequency emissions from a cell tower on the roof of Deering High School this week.

Superintendent Emmanuel Caulk said the teachers’ concerns were the first he’d heard regarding the tower, which has been in place since 2006. He ordered the tests after a biology teacher reported that fish she kept in Room 305 – located right below the tower – kept dying.

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According to the American Cancer Society and National Cancer Institute, most scientists agree that emissions from cellphone antennas or towers are unlikely to cause cancer.

“To date there is no evidence from studies of cells, animals or humans that radio frequency energy can cause cancer,” the National Cancer Institute says on its website.

The Federal Communications Commission says radio frequency emissions from antennas used for cell towers result in exposure levels on the ground that are typically thousands of times below safety limits. The agency monitors RF radiation for possible impact on the environment, including human exposure, according to the FCC website.

“There is no reason to believe that such towers could constitute a potential health hazard to nearby residents or students,” the website says.

However, critics of cell towers note that cellphone emissions are classified by the World Health Organization’s International Agency for Research on Cancer as possibly carcinogenic to humans. In a 10-year review of research from 13 countries, the agency didn’t find a causal relationship between radio frequency energy and cancer, but couldn’t rule out the possibility.

EXPERTS DIFFER ON POSSIBLE DANGERS

“This has actually been the subject of debate for many years,” said Ali Abedi, a University of Maine associate professor of electrical and computer engineering who has done wireless communication research for almost 20 years, including for NASA, the Department of Defense and the National Science Foundation.

Abedi doubts the fish died from proximity to the tower, because radio frequency waves barely penetrate water. They also don’t damage DNA like X-rays do, but instead generate heat, the same way that microwaves operate. An excessively high concentration of radio waves from a cell tower could, hypothetically, cause a burn or excessive heat.

“Maybe if (the fish) spent a lot of time on the surface,” Abedi said, noting that no conclusions could be reached unless experiments on the fish were done in a controlled, scientific manner. “I really doubt this is the cause of the fish dying.”

Joel Moskowitz, director of the University of California Berkeley’s Center for Family and Community Health, is among those advocating for stricter cellphone and cell tower standards and warnings. Moskowitz, who was a postdoctoral fellow in Evaluation Research and Methodology at Northwestern University, believes people should be more concerned about emissions from cellphones and cell towers based on his review of studies that linked cellphone emissions and biological problems in humans.

“We can’t just assume because the exposure is low from a cell tower that you’re OK,” he said.

Deering High biology teacher Polly Wilson says she knows her experiments aren’t proof the cell tower is causing the fish to die.

“This is high school science. There’s a lot of room for error. I would love if someone, some lab, picked this up and tried it in a more controlled way where they can measure it,” she said. “But I think it’s very compelling. Something is killing the fish in this room.”

MULTIPLE SOURCES OF EMISSIONS IN SCHOOL

The Portland School district gets about $36,000 a year for leasing the roof space to U.S. Cellular. There are no other cell towers on district property, said Craig Worth, deputy chief operations officer.

U.S. Cellular added three more antennas to the array in 2011, for a total of six. The company issued a report after those additions, in January 2012, that found RF readings were below FCC safety standards throughout the building and school grounds. However, it did note that the highest readings inside the building were in Room 305.

The report also noted that the building has multiple Wi-Fi hotspots, including one right in the middle of the ceiling of Room 305, which can affect and increase the readings.

UC Berkeley’s Moskowitz said he suspected any elevated RF readings in the room with the fish would be attributable to the router, not the tower, since towers direct their radio waves outward, not downward.

Worth said the tests this week measured RF levels with the high school’s Wi-Fi on and off. Results of the tests are expected in a few weeks, school officials said.

The FCC allows an ERP – effective radiated power – of up to 500 watts per channel. Most cell towers in urban and suburban areas operate at an ERP of 100 watts per channel or less, corresponding to an actual radiated power of 5-10 watts, according to the FCC website. The FCC last updated its guidelines for evaluating human exposure to RF fields from fixed antennas used for cellphone service in 1996.

STUDENT EXPERIMENT HAS FATAL RESULTS

Wilson has been teaching marine ecology in Room 305 for about 16 years, always with tanks of fish and other living things. It was only three years ago that the fish started to die, she said.

This spring, the students used aluminum foil to shield the tops and sides of four aquariums containing comet-tailed goldfish from radio frequency waves.

“We left them in there over Memorial Day weekend, we came back and they were fine,” Wilson said. “At that point, we took one of the foil (cages) off and 36 hours later, the fish died.”

The other fish, in the three shielded aquariums, were fine and are still alive, Wilson said.

Her students started a blog – called “Why Do Fish Die in Room 305?” – where they recorded their findings. The home page has a photo of a fish belly-up in a tank, with a Post-it note reading: “Begin: 5/7 Fish alive … 5/11 dead.”

“Our class noticed how we were unable to keep goldfish alive. Eliminating all theories as to what might be causing the death (food, water, pH, nitrite and nitrate levels) we came to the conclusion that the cell tower located above our classroom may be affecting the lifespan of the fish,” students wrote in the blog.

For Wilson, the dying fish prompted her to abandon her classroom of 16 years and teach in a vacant room.

She said her students found the experience “eye-opening.”

“They don’t think about their cellphone. … They think of it as totally benign. They were surprised and intrigued and interested in learning a little bit more,” Wilson said.

TWO TESTS, SCHOOL BOARD INVOLVED

Wilson’s husband, Gus Goodwin, asked School Board President Sarah Thompson to hold meetings on the issue. Thompson said she would raise the issue with school officials, but that it likely won’t be taken up until the fall.

“I don’t want to be the face of this. It’s a community conversation,” said Goodwin, who teaches technology education at King Middle School. “I care because someone I love teaches there and sometimes it’s easier for someone on the outside to ask the questions.”

Caulk said he ordered the tests to be conducted after a May 27 meeting of the teachers and district officials. U.S. Cellular did tests on the tower on May 29, he said, but the district decided to get a third-party analysis and hired C Square Systems in Auburn, New Hampshire, to conduct a four-hour test on Tuesday.

Goodwin said he thought the district was being very responsive and the meeting with district officials was “very productive.”

Caulk did not grant permission to the Portland Press Herald to visit the school Wednesday.

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