Project Overview
Soot and metals sampling for a fire restoration contractor after a lithium battery fire, repeated until a product development lab matched background levels.
The Challenge
A lithium battery caught fire inside a product development lab at a large corporate facility. Smoke and odor spread into nearby hallways, a mail room, a café, and the HVAC system.
The building owner set a strict timeline, and the restoration contractor had to meet it. Clearance on a job like this is rarely one and done. Every failed round means more cleaning, more sampling, and another wait for lab results, and each delay pushes the schedule back.
The contractor needed answers fast: where residue settled, what to clean, and when it was clean.
What We Did
Our team collected 179 surface samples over 9 site visits, supervised by our Certified Industrial Hygienist (CIH). We scheduled visits around the cleaning crew, including evening and overnight shifts, and took the contractor’s calls at any hour.
- Soot Sampling: collected 108 tape lifts for combustion by-products (CBP), meaning soot, char, and ash, read by polarized light microscopy (PLM).
- Metals Sampling: collected 71 wipe samples over 100 cm² areas for 7 metals, including nickel, cobalt, and lithium.
- Background Comparison: sampled an unaffected cafeteria and ran field blanks, per the 2018 AIHA Technical Guide for Wildfire Impact Assessments.
- Clearance Rounds: retested failed lab sections over 4 rounds.
- On-Site Guidance: walked the crew through each failed area, pointed out problem surfaces, and talked through cleaning methods.
- Reporting: delivered a CIH-signed report with findings and recommendations.
The Result
A job like this typically takes at least 4 weeks and can run for months. Through close communication with the contractor and a tight schedule, we finished clearance sampling in 16 days.
Before cleaning, 21 of 37 samples rated Moderate or Overloaded. Soot peaked at 96.77 counts per mm² vs 0.20 to 0.51 at background, and nickel at 82,000 µg/100 cm² vs < 4.0 µg. Neither has a regulatory limit, so background set the bar. We recommended:
- HEPA vacuuming and damp wiping.
- HVAC cleaning to ASHRAE guidelines.
- Removal of porous items that could not be verified clean.
The final 2 samples came back Light. Our CIH found all sampled areas comparable to background, and the contractor met the owner’s timeline.
Is the fire residue really gone?
A-Tech's Certified Industrial Hygienists sample soot and metals after a fire and show you, with data, when cleanup is complete.
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