We already knew that the EPA considers anything at three times background to be “significantly” above background, hence why we make special note of when any media we test comes above background. But what we didn’t know is that following readings actually qualify as hazmat-level high for the California Highway Patrol.
This rain reading came right off the coast earlier today:
7:25pm SPOT CHECK SANTA MONICA RAIN: ~166 CPM sustained or 415% of normal higher (Videotaped)
7:20pm INTERIOR RADIATION STATION BACKGROUND: ~40 CPM^
Thanks to our friend and colleague over at Potrblog, we found out that the CHP defines a hazmat incident as anything three times background or higher, which then triggers certain protocols by the agency as the fascinating following report indicates:
AGREEMENT STATE REPORT- LINEN TRANSPORT TRUCK DETAINED AFTER SETTING OFF RADIATION ALARM
The following information was provided via email:
“On 12/8/11 at 1430 PST, the Nevada Radiation Control Program (NRCP) received a call from the Alternate Radiation Safety Officer (ARSO) for Renown South Meadows Medical Center, that a truck carrying linen had been detained by the California Highway Patrol (CHP) at the Truckee inspection station after setting off a radiation alarm. The ARSO explained that the truck was not carrying any materials from the Nuclear Medicine Department or decay room and she knew of no reason that it would be radioactive. She provided the name and number for the CHP at Truckee.
“The NRCP contacted the CHP and were told that they had surveyed the truck with a Ludlum meter and measured .400 millirem per hour (or 400 microR/hour) outside the trailer. The CHP said that their protocols dictate that anything above three times background is treated as a hazmat incident and must have proper packaging and manifest. They had not run an identification spectrum on the truck. They had no capability to unload a trailer on site for further investigation. They were holding the vehicle pending instructions from their departmental radiation specialist and agreed to call [the NRCP] when they had a decision.
“The Aramark (linen service) representative confirmed that the vehicle in question was a tractor trailer and was carrying only linen from Renown.
“At approximately 1545 PST, the CHP called and indicated that they had released the trailer with orders to return to Renown Medical Center. They were unable to identify the radioisotope present and the dose rate reading was now .100 millirem per hour (100 micro R/hr).
“The NRCP Incident Response Supervisor arrived at Renown Medical center at approximately 1645 PST, shortly after the truck, and met with Renown staff. After conducting a radiation survey on the outside of the truck, he determined the general location of the high radiation and identified Technetium-99m (Tc-99m) as a suspected isotope. Linens are transported in large plastic bins, which were removed with a pallet jack, by the staff at Renown. When the radioactive bin was identified, it was segregated, a thorough survey was done and the radioisotope was positively identified as Tc-99m. The bin was placed in Renown’s decay room where it will remain for 2 to10 days until the Tc-99m decays.
“The most likely cause of this contamination was that a recently treated patient soiled the sheets and the possibility of radioactive contamination was not recognized by floor staff. Linens are not routinely screened for radiation. Aramark recently began transporting linens to Sacramento, rather than processing locally, so they are now subject to inspection upon entering California. The RCP will assist Renown with some procedure changes that will minimize the chances of this happening in the future.
“Dose rate readings were one order of magnitude lower than what CHP reported. It is unknown why CHP was unable to obtain an accurate identification of the isotope.
“Radiation readings: RadEye – Background 6 uR/hr; at bin 48 uR/hr; Ortec MicroDetective – Background 65 counts per second; at bin 1800 counts per second; Renown 451P Ion Chamber – Background 6 uR/hr; at bin 52 uR/hr; Ludlum 14c with pancake G-M detector – at bin 1800 counts per minute.”
Nevada Report Number: NV110024
Note that once the suspected radioactive material, which had triggered the alarm, was tested, it came in at a whopping 27.7 times background according to a Ortec MicroDetective radiation detector.
This is a good example of how proper protocol reaction can yield an important result. It also confirms that anything that reads three times background or above should be taken very seriously, as seriously as the California Highway Patrol takes it.
In this case, the Los Angeles Basin was being pelted with radioactive rain at 4.15 times background or 115% above the CHP trigger!