Based on information provided by the FBI, the OSC decided to conduct sampling at the trailer location to determine if decontamination was necessary.  Information indicated the trailer was used for storage of certain items moved from the dojo to the trailer by the suspect.  The majority of the items were removed as evidence by the FBI.  A limited number of these items were determined to contain suspected ricin by the FBI and it is not believed the suspect processed the ricin at the trailer.

On May 30, 2013 EPA collected nine samples from various surfaces throughout the trailer.  Samples were collected from areas that were associated with items removed by the FBI, adjacent areas including counter tops and floors, bathrooms, bedroom floors and contact surfaces were also sampled.  The samples were delivered to the Mississippi Department of Health (DOH) lab in Jackson, MS. The sample evaluation by the DOH would consist of a two test process.  First the sample would be tested using the Polymerase Chain Reaction (PCR) method which looks for DNA of the gene that produces the ricin protein.  If the PCR indicates a positive result a second test, called Time-Resolved Fluorescence Immunoassay (TRFI), is conducted.  In the TRFI test, the lab uses an antibody that binds to ricin to enable them to detect it in environmental samples. It is a way to determine if the ricin produces toxin. If both the PCR and TRFI tests are positive then ricin is confirmed.  The PCR results for all the trailer samples were negative, so there was no need to run the TRFI test.  Based on the results, EPA does not anticipate any further actions at the trailer location. 

On June 4, 2013 EPA sampled the karate dojo location.  Based on information provided by the FBI, it is suspected that the ricin was processed at the karate dojo.  FBI sampling indicated suspected ricin in multiple sample locations.  After consultation with the EPA Consequence Management Advisory Team (CMAT), the National Homeland Security Research Center, the EPA OSC decided to decontaminate the dojo with a 10% bleach solution prior to conducting EPA sampling.  The inside of the dojo has bare concrete floors, with walls and other surfaces being open and accessible for decontamination efforts. 

USES removed suspended ceiling tiles in areas of concern, as well as carpet from an entry way at the front of the facility.  USES then applied the bleach solution with hand sprayers and mops to all floors and walls and the areas were allowed to dry overnight.  After the bleach solution was dry, EPA collected 33 samples, including field duplicates, from various surfaces at the dojo.  Sample locations were determined based on the past and potentially future uses of the facility. These areas included, bare concrete floors, walls (approximately 3-1/2 ft. – 4-1/2 ft. above the floor), bathroom sinks, p-traps and toilets.  A sample of the waste generated by EPA's cleanup actions was also collected.

 Of the 33 samples collected at the karate dojo, results from the MSDOH lab indicated three positive results using the PCR test.  The lab determined that the bleach picked up on the sample swap interfered with the TRFI test and therefore, TRFI testing would not be a reliable way to verify the presence of ricin in the three samples.  The three samples were sent to the Center for Disease Control (CDC) for further testing using a Ricin Component Multiplex Assay test (RCMA).  This test takes into account the presence of bleach and calculates the results accordingly. One sample collected from the floor of a small bathroom was determined to be negative for ricin.  Results for the other two samples, which consisted of a sample and duplicate sample from the sink and sink cabinet, were inconclusive. CDC provided the two inconclusive samples to their National Center for Environmental Heath (NCEH) lab who ran a Ricin Mass Spectrometry Activity Assay test on the samples. NCEH determined the results as inconclusive citing the bleach as a possible test interference.  To ensure EPA's response was protective of the public, the OSC decided to remove the sink and associated cabinet as a precaution.

EPA, START and USES mobilized to the site on June 24, 2013 to complete the cleanup.  EPA had USES remove the sink and its associated cabinet.  The old sink and cabinet were placed directly into a over pack drum. A new sink and cabinet were installed.

The roll off generated during EPA's June 4 activities, which contained ceiling tiles, carpet, and personnel protective equipment, was covered and transported to a Subtitle D landfill under a special waste designation.  The waste was handled similarly to asbestos waste where a designated landfill area is prepared for the waste and once dumped, the area is covered immediately.  The over pack drum containing the sink and cabinet was transported and handled in same manner at the landfill.

As part of the restoration operations at the facility, new carpet was installed in the entry way to the facility and new ceiling tile was installed to replace the tiles that were removed by EPA's contractor.

After completion of the decontamination activities and review and discussion of the sampling data by EPA, MSDEQ, and MSDOH, the MSDOH generated and provided property clearance letters to the two property owners.

 2.1.3 Enforcement Activities, Identity of Potentially Responsible Parties (PRPs)