People who live all their lives in homes on land rich in phosphate deposits generally have a greater chance of dying from cancer due to radiation exposure than nuclear submarine workers in Maine or soldiers who were stationed near atomic bomb test sites in Nevada, according to Environmental Protection Agency scientists.
For the first time, EPA has backed up its contention by calculating the comparative risks from varying forms of low-level radiation in light of a study of 133 homes built on phosphate land in Florida.
The EPA findings have angered Florida's substantial phosphate industri, raised new questiones about how radiation dangers are tto be determined over the long term, and broadened the national argument over health effects of a relatively new radiation threat arising from nature.
Phosphate, a phosphorous compound strip-mined in central and northern Florida, is a prime ingredient in fertilizers. More than 80' percent of the U.S. output comes from Florida; it is also mined in Idaho, Montana, North Carolina, Utah and Tennessee.
EPA's Florida study, released in March, concluded that lifetime exposure to radiation levels found in 15 percent of the surveyed homes could double the normal 3 percent risk of fatal lung cancer. The study assumed a resident lived for 70 years on phosphate land and spent 75 percent of the time indoors.
The Florida controversy peaked recently after Dr. William Mills, EPA's acting deputy assistant administrator, said he would be more concerned about living in a house on Florida phosphate land with low radiation levels than being more briefly exposed to the higher radiation of the 1950's atomic tests in Nevada. Following Mills' statements, EPA made some comparative calculations that would tend to strengthen his opinion.
Over and above the 2,900 Americans expected to die of lung cancer out of a group of 100,000, the EAP Office of Radiation Programs projected:
2,300 to 6,900 additional people would die of lung cancer if they spent a lifetime accumulating average radiation levels in the worst cases on Florida phosphate land.
190 to 440 additional people would die of cancer if they were exposed to the highest doses experienced by 13 percent of the submarine workers for 20 years at the shipyard in Portsmouth, N.H.
40 to 100 more people would die if they had been exposed to the highest levels found at the Nevada testing grounds in 1957.
(Using the sae calculation method on the theoretical 100,000 people, 1 or 2 adults and from 1 to 20 children would die from cancer from the highest levels of radiation detected in the general population during the Three Mile Island power plant accident near Harrisburg, Pa.)
EPA officials have speculated that "corrective action" would be needed in about 800 of the 4,000 homes built on phosphate land. Such action would include better insulation, improved ventilation and creation of "crawl spaces."
The actual incidence of cancer among people who have lived on the phosphate land has not been studied. This point is stressed by the industry and by agents seeking to sell reclaimed mine property.
"They paint a very black picture of people dropping like files, but phosphate has been mined in Polk County [heart of the industry] for 80 years.
Any problems would have shown up by now," said Tim Clarke, spokesman for the Florida Phosphate Council.
Industry officials were first perturbed when EPA, after a preliminary look in 1975, discouraged the state from permitting any new structures on reclaimed phosphate land. The industry says new mining techniques have reduced the radiation in land reclaimed since 1946.
But the conclusions also jolted residents who live on phosphate land that has never been mined. Although the study concludes that most high-level homes were built on reclaimed land, some homes on virgin land had above-normal levels too.
The Florida Phosphate Council and Florida congressmen have bombarded EPA with letters. EPA Office of Radiation officials say they have never faced a hotter political issue.
Mills and other EPA officials who have become involved in the controversy are standing by their positions.
The House Commerce oversight subcommittee, chaired by Rep. Bob Eckhardt (D-Tex.) plans a hearing today on radiation dangers of phosphate found in Florida, Idaho and Montana. The subcommittee is considering a recommendation to designate phosphate lands as hazardous waste sites eligible for federall funded cleanup.