Anecdotes

[Bruce Pickett <SHEA136@KGV2.bems.boeing.com>]

 In 1979, while still a graduate student, I became the health physicist (read
 that as the entire radiation safety department) for a research lab located
 across the street from my university (but not part of the university). Two
 incidents from that time stick in my mind.

 (1) Approximately 6 months prior to my taking over as the facility HP, there
 had been a tritium contamination incident. The gas chromatograph (GC) in one
 ofthe labs had a tritium impregnated foil. The exhaust line from the GC went
 to a room exhaust duct and SOP required that the fan for that duct be manually
 turned on whenever using the GC (the duct fan switch was conveniently located
 next to the GC). One morning, the researcher started using the GC, but forgot
 to turn on the fan switch. He worked in the lab for about eight hours with no
 ventilation of the tritium offgas from the GC. The then current HP somehow
 became aware of the situation (I'm not sure exactly how) and conducted a
 contamination survey using wipes and counting them in a liquid scintillation
 counter. The HP found tritium contamination throughout the GC lab, down the
 corridors of one wing of the building and into several adjoining labs.
 Urinalysis of the researchers showed positive tritium results, with the
 original researcher having about 10% of the maximum permissible body burden.
 The labs and corridor were isolated for about a week while the HP
 decontaminated the facilities. But given the nature of tritium, it tended to
 "hide" in cracks and crevices, so that even after all areas had been cleaned,
 tritium continued to creep out of its hiding places. Even six months later,
 when I became the HP, I was still finding tritium now and then in unexpected
 places. Daily contamination surveys and quarterly urinalyses for the
 researchers resulted from this incident.

 (2) Tritium and carbon-14 were the only isotopes used by the researchers at
 the facility. In one lab, the researchers were doing environmental uptake
 studies in ecosystems using various C-14 labelled compounds. To check for
 airborne C-14, we would run a particulate air sampler all day long in this
 room, then count it on a gas flow proportional counter (GFPC) the following
 morning. Before going home at the end of each day, the HP (me) was supposed to
 turn off the air sampler and change the filter paper so that it was ready to
 start up the next day. One day, I forgot to turn off the air sampler and it
 continued to run overnight. The following morning when I discovered this, I
 said "oops!" and changed the filter and went to count it. To my horror, my
 GFPC was registering thousands of counts per minute, and my immediate reaction
 was that we'd had a leak of C-14 in the lab. I recounted the filter paper
 using a thin absorber and the count rate went to zero, thus confirming in my
 mind that I was witnessing a low-energy beta emitter on the filter (the
 facility had no alpha-emitting isotopes). I immediately evacuated the
 researchers from that lab and isolated it. I reported this to the facility's
 RSO (more or less a figurehead, he was a senior researcher with little rad
 safety experience), and he went off to convene the radiation safety committee.
 I contacted the senior HP for the university radiation center across the
 street and explained what had occurred, and his first question was "Did you
 take into account the radon daughters?" Again I said "oops!" and went back to
 recount my filter. I found that the activity on this filter decayed with an
 apparent half-life of about 35-45 minutes. Also, by adjusting the GFPC
 voltage, I found that the materials on the filter were principally
 alpha-emitters. Since this was at a time before all the furor surrounding
 household radon, radon and its progeny up till then had only been an
 interesting note in my textbooks; the realization that radon was real and
 measurable came as a hard-won lesson for a budding HP, and I've never
 forgotten about it since. Following my realization of my faux pas, I went back
 to the lab and released it from isolation and explained to the researchers
 what had happened; they all laughed and went back to work. I then went to the
 RSO to inform him of everything, and he told me that the members of the
 radiation safety committee were upset because I had isolated the lab without
 their consent. I told the RSO that it was ridiculous to expect me to get a
 committee consensus when, at the time, there appeared to be a real threat to
 the safety of the workers. Well, he went back to the committee and appraised
 them of the facts. The next day the RSO called me into his office to say that
 the committee was now upset with me because I had released the lab from
 isolation without their approval, even though there had not actually been a
 problem. So out of this I learned two lessons: (1) remember radon, and (2)
 committees, much like packs of wolves, have a need to mark their territory, so
 they tend to urinate on things a lot.

    Bruce Pickett
    The Boeing Company, Seattle WA
    shea136@kgv2.bems.boeing.com

 "You and I travel to the beat of a different drum."
                                        - Linda Ronstadt