Asbestos Clearance Testing Houston, TX — Post-Abatement PCM
Written pass/fail clearance letters from PCM fiber counts per NIOSH 7400, accepted by OSHA and Texas DSHS. Same-day turnaround for samples received before 2:00 PM CST, so the containment comes down and reoccupancy is never the thing waiting on the lab. Analyzed in-house at 10200 East Freeway, Houston TX 77029 — inside the Ship Channel corridor.
Why the clearance letter is the real deliverable
It Releases the Space
A written clearance report with a specific pass/fail determination is what lets occupants back in. Until it exists, the containment stays up and the project is not finished, however clean the space looks.
Every Hour Is Billable
A crew, an enclosure, negative air units and a client's reoccupancy date all wait on one number. Same-day turnaround is not a convenience on a clearance job — it is the difference between one mobilisation and two.
It Is the Liability Record
The clearance letter is the document that gets produced years later if anyone asks whether the space was safe to hand back. A TX DSHS-licensed laboratory result with the criterion stated is what makes it defensible.
The Visual Comes First
Sampling before the space passes a clean visual inspection is the commonest cause of a failed clearance — and the most expensive, because the crew is standing by while the second round runs.
Where We Can Issue a Clearance Letter
We accept ship-in samples from anywhere in the United States — but clearance is the one asbestos service where the state your project sits in genuinely decides whether our report is usable. Read this before you plan an out-of-state clearance.
Texas and the Gulf Coast
Our home ground. Texas DSHS License #300529 covers PCM, so our clearance letters are accepted by DSHS. Houston metro courier pickup means samples can be moving within the hour.
AHERA Sets the Federal Floor
40 CFR 763.90 defines the federal clearance procedure for school response actions and permits PCM clearance by a laboratory in the AIHA Proficiency Analytical Testing program — a bar we meet.
Accredited to ISO/IEC 17025
NIOSH 7400 sits within our AIHA-LAP scope (LAP-101470) and our PJLA accreditation (137751), both ILAC-MRA signatories. The analysis itself is the same wherever the sample came from.
But the State Decides Acceptance
Technical competence and legal acceptance are two different things. A clearance letter is only as good as the regulator's willingness to accept the laboratory that issued it.
Clearance is the one service where the state matters most
Many states impose two separate requirements on clearance — a licensed laboratory and, often, a licensed person to collect the samples. Several jurisdictions will not accept a clearance report from a laboratory that does not hold their own credential, including New York, Pennsylvania (and the City of Philadelphia separately), Massachusetts, Vermont, Connecticut, Rhode Island, Maine, Virginia, West Virginia, Hawaii and Louisiana. In Texas, clearance samples must also be collected by a DSHS-licensed Air Monitoring Technician. We hold the Texas laboratory license (#300529). Before planning a clearance outside Texas, call us — we will tell you plainly whether we can issue a report your regulator will accept, rather than let you find out at the end of the job.
What Post-Abatement Clearance Testing Proves
Clearance testing is the last step of an abatement project. After the containment has been cleaned and passed a visual inspection, air samples are drawn inside the abated area and analyzed by phase contrast microscopy. The result is a fiber concentration and a written pass or fail determination against the criterion your project is held to.
It is not the same job as exposure monitoring. PCM exposure monitoring asks what a worker breathed during the work; clearance asks whether the space is fit to hand back. Different criterion, different sampling protocol, different report — even though both are PCM analysis under NIOSH 7400.
- PCM clearance air sampling analyzed per NIOSH 7400
- Written clearance letter with an explicit pass/fail determination
- Criterion stated on the report — AHERA, TAHPR or your project specification
- Accepted by OSHA and Texas DSHS for commercial and industrial reoccupancy
- Same-day turnaround for samples received before 2:00 PM CST
- Priority resample handling for account holders on a failed clearance
Who does what
AGT Labs is an analytical laboratory. The clearance air samples are collected by your project monitor, consultant or licensed air-monitoring technician; we analyze them and issue the clearance letter from the result. We do not perform the visual inspection or the field sampling.
When Asbestos Clearance Testing Is Required
Where the project specification and the regulation differ, the specification usually governs. Send it with the samples and we will report against the criterion it names.
The Clearance Sequence — Visual Inspection Comes First
Skipping or rushing step two is the single most expensive mistake on a clearance job.
Abatement Complete
Work finished, but the enclosure and negative pressure stay up until clearance passes. Do not break containment early.
Visual Inspection
No debris, no residue, no visible dust. Air sampling before a clean visual is wasted money — settled dust gets counted regardless of its source.
Air Sampling
Inside the abated area, breathing-zone height, under aggressive conditions where the protocol calls for it. Minimum 1,200 L per sample.
PCM Analysis
Counted by TX DSHS-licensed microscopists in Houston per NIOSH 7400. Same day if received before 2:00 PM CST.
Clearance Letter
Fiber concentration, criterion applied, explicit pass/fail determination, analyst signature and QA sign-off. Containment comes down.
Clearance Sampling Requirements
Clearance sampling differs from exposure monitoring in volume, placement and blank count. These are the parameters we analyze against. Cassette handling, calibration and field blanks are covered step by step in how to collect asbestos air samples for PCM.
Aggressive vs Non-Aggressive Clearance Sampling
It does not change the analysis, but it changes what the pass means — and it belongs in the letter.
Aggressive Sampling
Settled dust is deliberately disturbed before and during collection — typically a leaf blower directed at surfaces, then fans running for the duration of the sample. The logic is straightforward: a space that passes while dust is actively airborne will certainly pass under normal occupancy.
Non-Aggressive Sampling
Collection under still conditions with no deliberate disturbance. Produces lower fiber counts and is a materially weaker demonstration that the space is clean. Use it only where the project specification explicitly calls for it.
Recording It on the COC
Tell us which method was used. It does not change how we count the filter, but it goes in the clearance letter — a pass under aggressive conditions and a pass under still air are not the same claim, and the letter should say which one it is.
How the Pass/Fail Determination Is Made
Each sample yields a fiber concentration in f/cc from the count and the volume drawn. That is compared against the clearance criterion for the project.
| Context | PCM criterion | Source |
|---|---|---|
| AHERA school response actions | 0.01 f/cc | 40 CFR Part 763 Subpart E, Appendix A |
| Texas regulated projects | As set by TAHPR / TX DSHS | Confirm against the current rule and your project specification |
| Commercial specifications | Usually the AHERA figure, sometimes stricter | Project specification — send it with the samples |
What the clearance letter contains
The concentration for every sample, the analytical sensitivity achieved, the criterion applied, whether sampling was aggressive or non-aggressive, and an explicit pass/fail determination — carrying the analyst's signature, QA sign-off and the accreditation numbers the result rests on. Delivered through a secure portal, accepted by OSHA and Texas DSHS.
What Happens If Clearance Fails
A failed clearance is not a disaster, but it is a stop. The containment stays up, the area is re-cleaned, and the space is resampled. Two things are worth understanding before it happens.
PCM counts all fibers, not just asbestos. A fail in a building with fiberglass insulation, mineral wool or fresh drywall dust may reflect non-asbestos fibers entirely. PCM cannot separate them — that requires transmission electron microscopy, and we do not hold TEM scope. If a clearance fails in a high-background environment, that is worth factoring into the re-clean decision.
Most failures trace back to the visual. Sampling before the space is genuinely clean is the commonest cause and the most expensive one, because the crew, the enclosure and the negative air units are all standing by while the second round runs.
- Containment stays up — do not break the enclosure on a fail
- Re-clean, then re-run the visual before resampling
- Resamples go to the front of the rush queue for account holders
- High-background buildings: consider what else is airborne before assuming asbestos
- Where fiber identity must be resolved, TEM is the method — call and we will point you to it
Same-Day Clearance for Contractors on Schedule
Clearance is the one asbestos analysis where turnaround is the service. A crew, a containment and a client's reoccupancy date are all waiting on a number.
Pre-Labeled Clearance Kits
- 25 mm MCE cassettes, 0.8 µm, scoped to the specific job
- Field blank cassettes — minimum two per clearance batch
- Lot-certified, calibration-traceable media documentation
- Pre-numbered Asbestos COC with a clearance section
- Volume and placement reference card — 1,200 L, 4–5 ft
- Pre-paid UPS return shipping label (domestic)
Kits ship ahead to account holders scoped per job. Order with 5 business days notice: (713) 453-6090.
Standing Clearance Accounts
Contractors who clear regularly should not be re-quoting every job.
Volume Pricing & a Named Contact
Agreed rates across all clearance and PCM work, and a dedicated lab contact rather than the general line — someone who knows your jobs and your turnaround pattern.
Kits Shipped Ahead, Scoped Per Job
Pre-labeled clearance kits sized to the specific project, with the right blank count and a pre-numbered COC, sitting on your truck before the job starts.
Priority Rush — Including Resamples
Same-day and 1-day turnaround held for account holders, and resamples on a failed clearance go to the front of the queue rather than the back.
One Submission, Whole Survey
Pre-demolition surveys run on one submission — PLM asbestos alongside lead, PCB and mercury, one chain of custody.
Monitoring Through the Job
PCM personal and area monitoring during abatement from the same account, so the exposure record and the clearance letter come from one laboratory.
Ship Channel Courier
We are at 10200 East Freeway inside the Ship Channel corridor. Houston metro courier pickup means samples can be moving before your crew has broken for lunch.
Asbestos Clearance Testing — Frequently Asked Questions
Answered by the accredited microscopists who issue the clearance letters.
What is post-abatement asbestos clearance testing?
How fast can I get a clearance result?
When is clearance testing required in Texas?
What is the clearance criterion?
Why does the visual inspection have to come first?
What is aggressive sampling and do I need it?
How many clearance samples do I need?
What happens if the clearance fails?
Can AGT Labs do the clearance sampling for us?
Is a PCM clearance letter accepted by Texas DSHS?
Do you offer TEM clearance?
Do you offer standing clearance accounts for contractors?
Clearance Samples on Site Right Now?
Same-day turnaround for samples received before 2:00 PM CST. Houston metro courier pickup available — call and we will collect while the containment is still up.