Re: crosspost: OEM: Carcinoid tumour of thymus / radioisotope exposure

[c0etxlim@mrd42.mrd.usace.army.mil (Luke I. McCormick)]

 In a previous life I was a Cased Hole/Production Logger for about 10 years. All the nuclides referred to except I-131 were pretty common. I-131 was used only for tracer logging. It came in the form of NaI dissolved in water. Though I can't speak for all companies, I worked for Schlumber ger and Gearhart and both provided extensive safety training for all sealed sources and I was sent through a specialty school for Radiotracer logging which did a pretty good job of explaining safe handling preocedures.  Safety procedures in the areas where I worked were pretty rigorously enforced. IN South Texas there was an accidental injection of I-131 from the tool in the riser, th riser was opened and the I-131 dripped out onto a couple of operators. They were flown to Houston for examination, and 3 55 gallon drums of contaminated soil were dug up and disposed of. "Cavalier' attitudes are always out there, but the vast majority of us were safety minded. 

The I-131 probably provided the most chance for accidental exposure. The Procedure for handling it involved removal from the rubber sealed vial by syringe and injection into the tracer tool fill port. More advanced tools had the syringe screw into the injection port and the tool 'sucked the I-131 into the chamber.
SOP was that all this was done over rags to prevent any dripping into the ground. On the wells I worked, we usually only used 3 mCi. per well.

We also did some logging on steam injection wells, where we fabricated a chamber to hold the Iodine, pressurized the chamber to above the steam injection pressure the opened the chammber into the injection line.  The vast majority of the Iodine went into the well, but there was always some contamination inside the chamber.  SOP was to use the chamber, seal it up, and decay it for 90 days before next use. 
There was usually some detectable contamination on the access valve to the injection well when we finished. SOP was to screw a gage into the valve, hang a caution RAM sign on the gage and leave it alone for 90 days.
Frisking was done after each procedure, though admittedly at a faster rate than it shuold have been.  We occasionally found some slight contamination; usually on sleeves and occasionally on wrenches.

At the locations where I worked ( S. Texas, Louisiana, Southeast Asia) ALL engineers and operators were on a film badge program. External exposures somtimes reached 100 mrem per month for some of the open hole loggers but usuallty much less for the cased hole loggers, as we rarely used the Big gamma and neutron sources.  My dose history for the 10 years I was logging is 2330 mrem Deep dose.

I hope this may put some perspective on the industry.  I sympathize with a fellow logger, and hope his tragedy can teach others about the importance of safe handling procedures with radioactive materials, but the original message has a note of condemnation for the whole industry which is undeserved.

Luke McCormick c0etxlim@mrd42.mrd.usace.army.mil
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