Methods of Mold Investigation and Remediation: A Case Study

1. Methods of Mold Investigation and Remediation: A Case Study Dawn Bolstad-Johnson, MPH, CIH Christopher Hansen, CIH Michael Jimenez City of Phoenix

2. Municipal Courts employees complained of non-specific health effects and requested an indoor air quality investigation. A walk-through of the building revealed additional information: There was a severe water leak about three weeks prior to the complaint Background Info…

3. The water leak was a result of a pipe that had burst while being repaired. Several thousand gallons of water were released in a short time. The leak occurred in the basement area. Everyone was evacuated and a contractor was contacted to remove inches of standing water found throughout the basement. Background Info

4. The initial health effects reported included a municipal judge who reported that he had lost his voice while he was on the bench. Others reported non-specific symptoms and/or building conditions such as “feeling yucky”, “stuffy air”, not enough circulation, etc. Reported Health Effects

5. A walk through of the building revealed no visual evidence of mold growth on any of the affected wall systems. Our hypothesis: If there was mold growth it may be contained within the wall cavities in the affected areas. Indoor Air Quality Investigation

6. Both non-viable and viable area samples were collected simultaneously within areas where the health complaints originated. Additionally, 6 wall cavity samples were collected. 14 non-viable samples were collected utilizing Zefon Air-O-Cells 8 viable samples were collected utilizing an Andersen single stage impactor equipped with a malt extract agar (MEA). Sampling Plan

7. Sampling Methods • Non-invasive wall cavity samples were collected by removing an electrical outlet plate and placing the Zefon cassette near the existing hole in the wall. • The wall was tapped intermittently during the 3-4 minute sampling time.

8. Preliminary Sampling Results

9. Schematic Drawing 11 12 15 16 10 13 14 17 W M STORAGE Water Leak Source

10. The sample results proved that we had mold growth in the wall cavities. We had employees experiencing health effects. This building is scheduled for demolition within the next 9–12 mos. A $12M new courts facility is under the final stages of construction. The Dilemma

11. The Dilemma • We needed to remedy the problem: • Using the least amount of $$$, and • The least impact on the municipal courts system. (At least 4 courtrooms were shut down.)

12. Our insurance adjuster recommended a contractor to come in to: Clean/wet-wipe all walls Apply a biocide to all surfaces Followed by a chlorine dioxide bomb This solution appeared to be the best at the time as it would minimize down time and overall disruption of court activities. Proposed Solution No. 1

13. Management witnessed the contractor training his staff on our job site. Apparently, he had gotten his crew from a labor pool. We gave the contractor an opportunity to supply us with minimal OSHA compliance training documentation. They could not. Problems…

14. In the interim, additional sampling had been accomplished to determine the extent of the mold contamination. An additional eighty-one (81) samples were collected in the remaining occupied areas of the basement which had not been previously tested. Additional Sampling

15. Sampling Methods • Air Samples for viable and non-viable spores were collected simultaneously from the air delivery vent and the ambient room air. • A tent was constructed around the air diffuser to accomplish this task.

16. Sampling Methods • Additional non-invasive wall cavity samples were collected using a Zefon cassette and an existing hole in the wall as previously discussed.

17. Sampling Results

18. Schematic Drawing 11 12 15 16 10 13 14 17 W M STORAGE Water Leak Source

19. Additional sampling allowed us to clearly define affected areas. In order to control the potential hazard, we elected to complete remediation in a limited number of areas. All other areas were to be thoroughly cleaned with a 10% bleach and water solution. Seal the walls above the ceiling with poly and expandable foam and all existing wall holes (e-outlets, phone jacks, etc.) with 6 mil poly. Solution No. 2

20. Visible mold was found on drywall within the office during cleaning. The wall cavity samples in these areas were also high. Strategy change: Remove sections of drywall with visible mold in office areas. Findings

21. We hired a mold remediation firm to removed mold contaminated walls and do the plumbing repairs. Total Cost of Remediation: $57,165.00 Solution No. 2 Addendum

22. Remediation • Walls were cut about 4’ or at least 1’ above visible mold contamination. • All work was accomplished under filtered negative air.

23. Remediation

24. Remediation • Visible mold was found in the wall cavity.

25. Remediation • Clearance sampling was accomplished after remediation and cleaning were completed with non-viable spore traps.

26. Sample Results

27. All walls around courtrooms 12, 13, 14, 15, 16 and 17 were sealed using an expandable foam and plastic sheeting over holes. The wall between the men’s and women’s RR was removed as were areas within selected Judge’s chambers where visible mold growth was discovered. Conclusions

28. Schematic Drawing 11 12 15 16 10 13 14 17 W M STORAGE Water Leak Source

29. Building tents around air diffusers while taking simultaneous room samples will quickly show whether the HVAC system is contributing to the mold count in the room. There are non-invasive ways to check mold growth within wall cavity areas. While these samples cannot be compared to outside air, they will give you more info. Lessons Learned