Courthouse Clearance Failure and Sampling Independence
A county courthouse is abating 1,200 square feet of sprayed-on ceiling texture and mastic over a grand jury room and two adjacent corridors. The work is done over a holiday weekend. On Sunday the licensed abatement contractor completes final cleaning and the air sampling technician collects five phase-contrast samples inside the containment. Results are 0.013, 0.017, 0.009, 0.011, and 0.015 fibers per cubic centimeter; the average is 0.013. The technician's visual inspection notes a light gray dust film on the top edge of a supply duct and on the floor of the decontamination shower. The contractor's project manager says the dust is construction dust from outside the containment and proposes HEPA-vacuuming the duct, re-sampling Monday morning, and reopening the courthouse for a trial at 8 a.m. Tuesday. The air sampling technician is a full-time employee of the abatement contractor.
1. Do the clearance results permit reoccupancy? Address the average, the individual samples, and the visual inspection.
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They do not. Ohio's clearance criterion is 0.01 f/cc by PCM, and the five-sample average of 0.013 exceeds it. Individual results of 0.013, 0.017, 0.011, and 0.015 are also above 0.01, so the failure is not caused by one outlier. More fundamentally, a passing visual inspection is a prerequisite to clearance air sampling. The visible dust on the duct and in the shower means the visual inspection failed, which independently bars reoccupancy regardless of the air numbers. The project manager's explanation that the dust came from outside the containment is not a substitute for cleaning and re-inspection; the containment is supposed to prevent that migration. The space must remain posted and inaccessible, with containment and negative pressure maintained or re-established. The contractor should document the failure, notify the owner and project designer, reclean the affected surfaces, pass a new visual inspection, and then collect a complete new set of clearance samples. Reopening Tuesday for trial without a passing visual and clearance set would violate the program and expose occupants.
2. What must happen before re-sampling, and what is the significance of the technician being the contractor's employee?
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Before re-sampling, the contractor must keep or restore the containment and negative pressure, wet-clean and HEPA-vacuum all surfaces, including the top of the supply duct and the decontamination shower floor, and then pass a new visual inspection. Simply vacuuming one duct is not enough because the dust pattern suggests incomplete final cleaning. Only after the visual passes should a new set of air samples be collected. The technician's employment by the abatement contractor is a conflict of interest. The contractor has a direct financial interest in a passing result, and the owner cannot rely on the appearance of independence. Ohio requires clearance sampling by a licensed air sampling technician; on public projects and school projects, independence from the abatement contractor is a standard safeguard and often a contract requirement. The county should use an independent licensed technician, or at minimum have the owner's representative witness sampling and maintain chain of custody. The prior results are still valid as a failure; the issue is the credibility of any future passing result, not whether the failure can be ignored.
3. The contractor proposes one passing sample on Monday as sufficient. Is that acceptable?
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No. Clearance is not a single Grab sample. The project design and ODH requirements specify a sampling scheme, including the number and location of samples, and all samples must meet the clearance criterion. A single passing sample cannot cure the earlier failing set, cannot demonstrate that the entire contained area is clean, and would not satisfy the owner's duty to confirm abatement. The county should require the full re-sampling set after the visual passes, with chain-of-custody documentation and results reviewed before reoccupancy. If the contractor wants to open Tuesday, it should start recleaning immediately, not wait for a single sample. The county should also consider whether the contractor's failed final cleaning and proposed shortcut warrant a notice to ODH or a contract cure notice.