RANTOUL – A volunteer worker was cataloging aircraft materials at the Octave Chanute Aerospace Museum in Rantoul in November when he discovered a green warning sticker on the back of a gauge.
When he brought the gauge to the attention of museum curator Mark Hanson, Hanson said he was shocked.
"The green sticker meant the gauge had radioactive materials in it," Hanson said. "I had been assuming that everything in the museum would be safe, but there was radium in that gauge."
Hanson won't identify the volunteer except to say that the man was a college student and hasn't returned to do volunteer work at the museum since that day.
Hanson immediately called the Illinois Emergency Management Agency, which performs monitoring of radioactivity levels at public places like museums.
The agency sent out an investigator who did radiological tests on the museum's entire collection on Nov. 22.
The investigator, George Merrihew said he discovered radioactivity (mostly radium and thorium) in paint on aircraft instrument dials and equipment switches; in optical equipment on aerial cameras, octants and meters; in metal alloys on two jet engines; and in an emergency transmitter and engineer's panel on the museum's Lockheed EC-121 Constellation airplane.
In addition, an Air Force radiation expert who tested the collection in December discovered radioactivity in metal alloys on the museum's B-58 Hustler supersonic bomber.
Richard A. Allen, bureau chief for environmental safety for the Illinois Department of Nuclear Safety in Springfield, said health damage wouldn't be likely at a museum unless a person were exposed to the radiological materials for a long period of time.
"If you're keeping this stuff in a desk or sitting on it, I'd move it elsewhere," Allen said. "But if it is behind some glass, the materials should be safe."
While radioactivity levels on most of the items were below limits set by the Air Force and the Smithsonian Institution for museum exhibits (0.5 millirems per hour), the investigator discovered three items that were not safe according to those standards:
– An oxygen regulator tested at 2.1 millirems per hour, or more than four times the maximum amount.
– A "Gibson Girl" emergency transmitter also tested at 2.1 millirems per hour.
– A turning indicator tested at 2.5 millirems per hour, or five times the maximum amount.
For comparison purposes, the background radiation level at the museum is 0.007 millirem per hour.
Hanson had the three items removed from the public display area. Those and approximately 100 other artifacts with high radioactivity levels were placed under lock and key in an isolated storage area until the Emergency Management Agency provides the museum with procedures for their removal and disposal.
Hanson said the Air Force will remove all radioactive materials from the B-58 aircraft within the next few months.
Since the EC-121 plane was loaned to the museum by the Navy, which allows the presence of radium in its equipment, H. R. Curry of the National Museum of Naval Aviation gave the Rantoul museum approval to keep the plane on display as long as the gauges are not broken.
But the museum has put up barriers to keep visitors from getting too close to the EC-121.
Hanson said the materials are potentially dangerous to humans only if a person inhales air contaminated by radium or thorium particles.
According to the Environmental Protection Agency, exposure to those elements can increase a person's risk of getting cancer.
Breathing in thorium may increase a person's chances of development of lung diseases and lung and pancreas cancer.
Exposure to radium can result in teeth fracture, anemia, cancer and cataracts.
Hanson said nearly all the artifacts in question either came from Chanute Air Force Base when the museum was created or were donated by the University of Illinois to the museum when the university disbanded its school of aviation.
In addition, the museum's board of directors approved spending $2,038 for meters, detectors, bags, safety equipment, gloves and dust masks that Hanson will use to regularly test the museum's collection for radiological content and to reduce the radioactive risk.
"That's a small price to pay compared to the cost of a lawsuit, should that ever come up," said museum board member Marty Zvonar of Monticello.
How discovery will affect visitors
– Visitors, especially children and pregnant women, will no longer be allowed to enter the cockpit of any aircraft that contains radioactive gauges.
– Aircraft with radioactive gauges shall have their canopies closed at all times.
– Large aircraft will have internal barricades preventing visitors from entering into the cockpit or other high-risk areas.
– The hoods of two aircraft trainers will be kept closed at all times.
"We're open to the public, and we don't want this to be a hot spot for them," said museum Executive Director Jim Snyder.
In addition, any time a donation is made to the museum's collection, museum staff will be required to monitor the items for radioactivity.
You can reach News-Gazette staff writer Tim Mitchell at (217) 351-5366 or via e-mail at email@example.com .