State finds high levels of cancer-linked radon in some S. Florida homes
State finds high levels of cancer-linked radon in some S. Florida homes
By Neil Santaniello
November 21, 2004
It's an indoor air threat -- a cause of lung cancer -- that slips invisibly into a home. You can't see, taste or smell radon, a radioactive gas exhaled by the ground below you, created by disintegrating uranium in rock and soil.
Out of sight, radon also remains out of mind for much of South Florida.
Many people know little about the naturally-occurring gas, despite estimated deaths of between 15,000 and 22,000 people a year, according the National Academy of Sciences.
Yet, according to test results compiled by the state, radon invades thousands of South Florida homes at levels the federal Environmental Protection Agency deems potentially dangerous to inhabitants.
Measuring radon indoors is easy and often inexpensive, requiring nothing more complicated than a shoe-polish-size canister of activated charcoal for starters. But most homeowners don't bother. Some cling to the perception that radon is mainly a hazard oozing out of rockier northern areas, where houses are dug right into the earth -- not in sandier Florida, where most homes are built on top of flat, supporting concrete slabs.
The state department of health, however, calculates that about 750 Floridians a year die of radon exposure.
"In general, most people don't think there's radon in Florida," said Doug Wall, a Naples-based professional radon measurer. "`We don't have basements' -- that's the first thing out of their mouths -- `We can't have radon here.' Well, radon is everywhere."
Indeed, radon tests around South Florida have found potentially harmful levels of radon dotting the tri-county map, levels that regulators say should provoke changes to homes to reverse the condition. The results were gathered by the health department's office of Radon and Indoor Air Toxics from state-certified radon testing, and companies that specialize in reducing radon in homes.
Of 3,468 Palm Beach, Broward and Miami-Dade residences measured for radon for the first time from 1999 to 2003, 37 percent, or 1,290, had radon at or above the EPA action level of 4 picocuries per liter of air, state records show. Under Florida's radon protection program, those tests are optional, unlike mandatory inspections required of health and child-care centers and of elementary schools operated or regulated by the state.
Forty-six percent of the multifamily homes checked during that time frame, and 5 percent of the single-family homes, had high radon levels, the state figures show.
A picocurie is a measure of radioactivity equal to the disintegration of about two radioactive atoms per minute.
The EPA's radon danger line of 4 picocuries, 10 times the amount of radon generally found in outdoor air, is a nonenforceable public health guideline. Exposure to that much radon is the same as soaking up 200 chest X-rays per year, and creates a cancer risk similar to that for a smoker who puffs on half a pack of cigarettes per day, the EPA says. The incubation time for cancer caused by radon is about four decades. "You don't get it tomorrow because you get a whiff of it today," said Thomas Pugh, director of the Institute for Building Scientists at Florida A&M University. "It should not be a panic-producing thing," but it shouldn't be ignored either, he said.
If levels reach 4 picocuries, the agency recommends such home modifications as sealing off potential radon entry points or adding equipment, and often fresh-air intakes, pipes and fans, to increase air pressure in a home and thwart radon accumulation.
Tests results vary widely
The state compendium of radon tests shows four times as many multifamily homes -- largely rental apartment complexes -- tested from 1999 to 2003 than single-family homes. Rental complexes change ownership periodically in major commercial real estate transactions that often mandate environmental audits. Those audits systematically look at contamination problems, including radon, sending professional radon testers sweeping through buildings as part of the real estate transaction.
Homes differ in their radon vulnerability, according to the U.S. Geological Survey. Radon can reach potentially toxic levels at one house but remain benign next door, so paying for a radon test -- which can cost $10 to $20 for a do-it-yourself version, or $150 or more for a professional assessment -- makes sense, said Kristy Miller, an EPA spokeswoman. "That's the only way to know for sure," she said.
In South Florida over about the past half-decade, harmful radon levels have cropped up at several properties, including: Amli at Ibis Apartment Homes on Northlake Boulevard west of Beeline Highway; Via Lugano Apartments in Boynton Beach; Sherwood Forest at Coral Springs; and Plantation Colony Apartments in Plantation. All subsequently added or are installing equipment to control radon, their managers or other representatives said.
During the past five years, recorded radon levels have crept as high 33.2 picocuries -- eight times the EPA radon action level -- in the tri-county area. The top reading occurred in a single home in the 6700 block of West Oakland Park Boulevard in Lauderhill, but remains well below the peak radon reading recorded in all of Florida so far: 267 picocuries in Gainesville, state health officials said.
The Earth belches radon from radium -- a decay product of uranium -- with the help of fissures in rock and the pores between grains of soil, which allow the gas to escape. Radon goes into the atmosphere or is trapped in homes, pushing through various apertures: the cracks in concrete slab, for instance, or the gaps girdling pipes that penetrate indoors. Rock incorporated into home decor and other building materials and well water can also emit radon.
"If radon is able to move easily in the pore space, then it can travel a great distance before it decays, and it is more likely to collect in high concentrations inside a building," according to the Geological Survey's "The Geology of Radon."
With air pressure in the ground and around a home generally greater than the pressure inside it, an imbalance is created that draws radon indoors. The gas can then pool inside basements and crawl spaces, on ground floors and higher.
As radon decays, it releases atoms of heavy metals called alpha particles, or "radon daughters." Those daughters latch onto particles of smoke and dust that people inhale with the air. If the particles become mired in lung tissue, they can bombard it with cell-damaging radiation.
Often a basement or ground-floor threat, elevated radon also can appear much farther upstairs in Florida, in the upper floors of some high-rise condos and apartment buildings.
Harmful levels have appeared as high as the ninth floor of a building at 410 Flagship Drive in Naples, state records show. Naples radon tester Wall said he has measured excessive radon even higher up in buildings, inside 20th-floor penthouses.
That has fueled a belief that radon is emitted from the walls, ceilings and floors of high-rise homes formed from cubes of concrete. Concrete is forged from aggregate such as gravel or crushed stone, sand and cement -- stuff quarried out of the ground where radium is found.
Proponents of this radon-from-concrete explanation say that the escaping radon is being concentrated by steamy Florida's energy efficient building code, intended to keep cooled air from escaping from homes. The relatively airtight homes the code engenders likely trap the gas, they argue.
"It's a strong hypothesis," said Clark Eldredge, a radon specialist in the bureau's Radon and Indoor Air Toxics office.
Others argue that radon more likely is traveling from the ground upward through building chases -- conduits that carry plumbing and electrical lines -- or other vertical passageways such as elevator shafts and garbage chutes.
"The sources that you're getting from the upper floor may be from the earth several floors below," Pugh said. "It may not have anything to do with the materials of the building." Pugh considers it "very doubtful" that building materials generate a radon hazard on their own.
Howard Singer had his Boca Bath & Tennis condo checked for radon in 2001. The retired New York textiles salesman learned he had levels of 8 picocuries in his condo at St. Tropez, on Boca Club Boulevard -- twice the EPA danger level of 4.
Singer's radon quickly fell to 2.4 picocuries after he spent $1,300 to equip his home with a radon reduction system. The last measurement taken, in March 2002, found radon had crept up to 3.1 picocuries but remained below the federal action level.
"I didn't even know what radon was," Singer said. "You never read about it."
Medical office manager Linda Quinines had no idea her rental unit at Plantation Colony Apartments in Pembroke Pines had tested high for radon -- 10.5 picocuries -- in 2000. She did not recall anyone from management raising the issue when she moved into the complex on Southwest 12th Street two years ago. She said no one told her about the radon reducer that came with her apartment.
"I definitely would have liked to have known about it," said Quinines, who lived there with her two sons, husband and a dog. They are moving out in May but radon didn't chase her off; her family simply bought a new home, she said.
Donna Barfield, an attorney speaking for the complex owner, said the radon systems brought the gas down to safe levels. She said the devices are on a maintenance schedule to keep them operational. She said she knew of no radon information in Plantation Colony rental leases "other than the standard radon disclosure" required for real estate deals.
State standards optional
Government maps highlighting more radon-prone geography point to mountainous areas of the United States, the upper plains and stretches of the Midwest, and parts of the northeast. Pennsylvania and New Jersey have radon-rich areas. Florida generally falls on the lower end of the nation's radon hazard scale, said David Rowson, director of the EPA's Center for Healthy Buildings.
Working against radon awareness is its lack of a signature in cancer cases. There's no telltale clue pointing to radon in a biopsy or autopsy.
Scientists and health officials estimate a death toll, and derive that figure from long-term studies of miners who work in virtual caves of radon below the ground, workers who have died from cancer "at rates five times the rate expected for the general population," the EPA reports.
"We didn't study rats, gerbils, hamsters or beagles: We studied people to come up with this," said Michael Gilley, a radon supervisor in the health department's Bureau of Community Environmental Health.
The Florida Building Code addresses radon prevention in new residential construction, but its radon-resistant building standards are optional -- tucked into the code's appendices. Counties can adopt them voluntarily but only one, Hernando, has done so, said state officials.
The standards -- developed by the Florida Department of Community Affairs from 1989 to 1995 with funding from a building permit surcharge -- were not made part of the regular building code because the issue was controversial and mandatory radon-proofing would boost construction costs, said Jack Glenn, technical services director for the Florida Homebuilders Association. Also, radon was an obvious problem only in some parts of Florida and officials "didn't want to paint the entire state with a broad brush," Glenn said.
The building code instructions basically prescribe a sealing regimen to keep radon from infiltrating a home -- a passive approach. The code does call for more active measures, such as mechanical radon reduction, which would have required more ventilation in homes and "that flies in the face of energy conservation," Glenn said.
Federal and state officials have created Internet tools to rough out radon potential in counties and states. One posted by the EPA can be found at www.epa.gov/radon/zonemap.html and designates three color-coded levels of escalating potential danger: yellow, orange and red. The EPA map takes into account indoor radon readings around the nation, geology, foundation types and soil permeability, EPA officials said.
Florida health officials offer tools that report radon measurements in the state database by ZIP codes at www.doh.state.fl.us/environment/facility/radon/index.html.
Residential real estate contracts in Florida flag radon as a potential problem in homes but not in a big way. They do include a mandatory three-sentence radon disclosure statement that warns homebuyers radon can occur in homes and "may present health risk to people exposed to it over time."
"Legally that's all the federal and state law require a Realtor to do," said Marla Marlin with the Florida Association of Realtors in Orlando.
Staff researcher John Maines contributed to this report.
Neil Santaniello can be reached at email@example.com or 561-243-6625
Copyright (c) 2005, South Florida Sun-Sentinel