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Residential Dust Wipe Procedures: FAQs


1. Who is paying for the residential dust wipe surveys?

The Navy is paying for the dust wipe work that CDPH anticipates beginning in mid-February 2019. The dust wipe procedures will be published on the CDPH web site.

2. What can wipe measurements detect?

These wipe measurements are intended only for detecting the presence of alpha/beta emitters. These alpha/beta emitters include plutonium and strontium that would be indicators of fallout washed from ships that had been part of atomic bomb testing programs in the past. The possibility that residual dust from parcels where these ship decontamination activities occurred might have been blown into residences was raised by some residents, so dust wipe measurements will be useful to see if any such contamination occurred. There is no need to perform scanning for gamma radiation in these dust wipes, because any dust containing gamma radiation would have been identified through the health and safety scan performed outdoors on A-1.

3. How are wipes analyzed?

They are placed in a sample counter where a detector assembly is placed over the wipe and the detector is hooked to a Ludlum Model 3030 detector for counting of the alpha/beta particles from the wipe.

4. How are the wipe locations determined?

The window sills were chosen because they would give the most direct samples of wind-blown dust, as requested by the residents.

5. Why are you only taking three wipes?

This is a reasonable number of samples given the average number of windows per unit.

6. When will residents get the results of the wipe survey?

The analysis is expected to take a few weeks to complete. Once the wipes for all residences have been analyzed, survey results will be recorded and provided to the authorizing resident via a report. These initial results will be placed in a sealed envelope, labeled with the requester’s name, and provided to the Homeowners Association’s management company for pickup by each resident.

7. How will unusual findings be handled?

CDPH will conduct follow-up evaluation for any unusual findings. If that analysis determines that a material with potential risk may be present, CDPH will coordinate further follow-up with the other agencies and the resident, including radiological characterization and next steps by the Navy. (See dust survey "Internal Procedures" document for details.)

8. When will a final report be published?

CDPH will publish a final report 6 weeks after completion of the project. The Final Dust Scanning Report will contain a summary of general results and the number of units exceeding trigger values, if any. No location-specific information will be included to ensure resident privacy. ​​

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