GORE, Okla., Jan. 9 – Thirty workers who were exposed to a corrosive radioactive gas here will be closely monitored for several weeks to see if they suffer any permanent health effects, according to a nuclear radiation expert who is following their progress.
The expert, Dr. Carl Bogardus, who is director of radiation therapy at the University of Oklahoma, said the main concern was that the workers could develop some irreversible kidney damage. It is possible, he said this week, that a type of long-lasting uranium particle could be lodged in their lungs.
”We won’t know exactly what happened to them for quite some time,” said Dr. Bogardus, ”We will be doing very detailed analysis of how much uranium they excrete and how much, if any, they retain.” The accident occurred Jan. 4 at the Sequoyah Fuels Corporation uranium processing plant near the Arkansas River in southeastern Oklahoma. A container of uranium hexafluoride ruptured, forming a cloud of highly corrosive vapor that killed one worker and injured 30 others. Seventy-eight people who were downwind from the plant were also exposed to the gas, but none were seriously injured.
‘No Indication of Kidney Damage’
The Kerr-McGee Corporation, which owns the plant, has received reports from urine analyses of all employees and residents tested after the accident, a company spokesman, Richard S. Pereles, told a news conference several days later. He said they showed ”to date no indication of kidney damage.”
Tests outside the plant show ”no member of the public had any seriously elevated levels of uranium in their urine,” he said, although there were high levels among some employees.
Dr. Bogardus explained that upon contact with water vapor in the air uranium hexafluoride immediately turns into a corrosive substance, hydrofluoric acid, with smaller amounts of radioactive gases mixed in.
The hydrofluoric acid is ”mean stuff,” he said, adding that a worker standing nearest the tank ”got it full in the face” and later died from extensive lung damage. Thirty other workers who breathed the hydrofluoric acid were exposed to less of the gas and were not expected to suffer long-term health effects from it.
Problems From Uranium
Uranium is another matter, he said. Dr. Bogardus said the workers could have been exposed to three types -uranium hexafluoride, uranyl fluoride or uranium oxide – but that the exact chemistry of the accident would not by known for several months.
Study of urine taken from the workers soon after the accident show that a number of patients excreted significant levels of uranium compounds, he said. Uranium hexafluoride and uranyl fluoride are extremely soluble in water and probably account for this finding, he said, and since uranium hexafluoride breaks down quickly on contact with air to form uranyl fluoride, he added, ”we are assuming most of the uranium in the patient’s urine was uranyl fluoride.”
Dr. Bogardus said that after the accident some workers had 10 to 100 times the five micrograms of uranyl fluoride per liter of urine normally found in most residents around the fuel plant.
Dr. Bogardus said urine samples would be taken from each worker every 24 hours for several more weeks. When the level of uranyl fluoride drops back to normal levels, he said, ”we hope to extrapolate the numbers to find our exactly how much uranium they passed through their systems.”
How Uranyl Fluoride Acts
Uranyl fluoride can be dangerous, he said. Although it dissolves in urine and can be passed out of the body, it behaves like other toxic heavy metals such as arsenic or mercury.
The kidney, he said, works by passing some elements into urine and by reabsorbing other elements into the bloodstream for re-use in the body. The reabsorption area of the kidney, the tubules, is very vulnerable to heavy metal poisoning. If too much uranium gets into the tubules, he said, it could permanently destroy cells.
The workers are taking Alka-Seltzer to make their urine more aklaline, he said. Alkaline urine tends to be less well absorbed by the tubules and may prevent some uranium molecules from reaching the vulnerable area, he said. The third uranium product in the accident could be uranium oxide, Dr. Bogardus said. ”Probably very little was formed,” he said, ”but it is more worrisome.”
Uranium oxide, when inhaled, may be deposited in the lungs and stay there a long time, he said. Later workers will be tested with a nuclear medicine instrument that detects uranium oxide in lungs. Such particles are radioactive and long-lasting.
If any is found, special drugs can be used to try to remove the uranium from the person’s body, Dr. Bogardus said.
”This is the largest group of people ever exposed at one time to uranyl fluoride,” he said. He said the group offered a rare opportunity to study the substance in humans.
Urine samples taken daily from the workers will be divided and sent to three laboratories for testing and analysis, Dr. Bogardus said. Kerr-McGee will conduct tests, as will the Nuclear Regulatory Commission. A third, independent laboratory wil also examine samples.