Crystalline Silica Testing Laboratory

As a premier crystalline silica testing lab, we provide XRD (NIOSH 7500) and FTIR (NIOSH 7602) analysis from our ISO/IEC 17025 accredited Houston facility. Personal exposure monitoring, respirable dust gravimetric analysis, and bulk material quantification — OSHA 1910.1053 and 1926.1153 compliant results accepted nationwide.

ISO/IEC 17025 Accredited AIHA LAP · ID: LAP-101470 Rush Turnaround Available In-House Houston Lab
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What's onthis page Quick links to page sections
Why It MattersOSHA & health
What Is It?RCS explained
4 Lab MethodsXRD · FTIR · Dust
Silica TypesQuartz · Cristobalite
Report DeliverablesAll methods & outputs
TAT & Free KitsRush options
Field GuideCyclone & flow rates
RegulationsOSHA · NIOSH · MSHA
Who We Serve6 industries
FAQCommon questions
Why Silica Testing Matters

Silica exposure is invisible — only air monitoring confirms your controls work

OSHA Enforcement

OSHA 1910.1053 and 1926.1153 carry penalties up to $16,131 per violation per day. Construction employers who skip Table 1 compliance or fail to monitor face stop-work orders and criminal referrals.

Silicosis Prevention

Silicosis is incurable and progressive. RCS particles that reach the alveoli trigger permanent fibrosis. OSHA's PEL of 50 µg/m³ was set precisely because lower concentrations still cause disease over a working lifetime.

Legal & Liability Shield

Workers' comp and tort claims for occupational silicosis are increasingly successful. Documented, accredited air monitoring history from an ISO/IEC 17025 lab is your primary legal defense against exposure claims.

Baseline Assessments

Employers are required to assess the exposure of each employee who is or may reasonably be expected to be exposed to RCS at or above the action level.

Industrial Hygiene Laboratory

What Is Crystalline Silica (RCS) Testing?

Crystalline silica is a mineral found in sand, stone, concrete, mortar, and many industrial materials. When workers cut, grind, drill, blast, or crush these materials, they generate airborne particles small enough to penetrate deep into the lung — called Respirable Crystalline Silica (RCS).

Silica testing measures the exact airborne concentration of RCS in the breathing zone of workers using personal sampling pumps, cyclones, and pre-weighed PVC filters. Our crystalline silica testing laboratory analyzes these filters via X-Ray Diffraction (XRD) or Infrared Spectroscopy (FTIR) and reports results in µg/m³ for direct comparison to the OSHA PEL (50 µg/m³) and Action Level (25 µg/m³).

  • Airborne RCS monitoring via XRD (NIOSH 7500 / OSHA ID-142)
  • Total and respirable dust gravimetric analysis (NIOSH 0500/0600)
  • Bulk material characterization for silica content
  • Quantification of specific polymorphs (Quartz, Cristobalite, Tridymite)
  • Defensible data for OSHA "Table 1" compliance alternatives
Construction worker wearing personal air sampling pump and cyclone for silica testing
Analysis Methods

Our Silica & Dust Testing Methods

As a specialized crystalline silica testing lab, we know that choosing the correct analytical method is critical for regulatory compliance and dealing with potential sample interferences.

METHOD 01

XRD Silica Analysis

X-Ray Diffraction (XRD) is the gold standard for crystalline silica analysis. It measures the specific crystalline structure of the particles, allowing accurate quantification of Quartz, Cristobalite, and Tridymite, even in the presence of interfering minerals.

Standard:NIOSH 7500 / OSHA ID-142
Media:PVC filter (37mm, 5.0 µm)
Report:µg/sample + OSHA PEL comparison
Best for:Construction, foundry, definitive compliance
METHOD 02

FTIR Silica Analysis

Fourier Transform Infrared Spectroscopy (FTIR) measures the absorption of infrared light by silica bonds. It is a valid alternative to XRD but is more susceptible to interferences from other minerals (like certain silicates or amorphous silica) present in the dust.

Standard:NIOSH 7602
Media:PVC filter
Report:µg/sample (Quartz only)
Best for:Environments with known, simple dust profiles
METHOD 03

Respirable & Total Dust

Gravimetric analysis to determine the total mass of dust collected. We highly recommend pairing Respirable Dust (NIOSH 0600) with your Silica XRD analysis to get a complete picture of the worker's exposure profile from a single filter.

Standard:NIOSH 0500 (Total) / 0600 (Resp.)
Media:Pre-weighed PVC filter
Report:mg/m³ dust concentration
Bonus:Can be run before XRD on the same filter
METHOD 04

Bulk Silica Quantification

Determines the exact percentage of crystalline silica in raw bulk materials — concrete, grout, sand, stone, aggregate, or industrial minerals. Required when an employer needs to characterize the silica content of materials before beginning work, or for SDS compliance documentation.

Standard:XRD / NIOSH 7500 (Modified)
Media:Bulk material (powder, chunk, slurry)
Report:% crystalline silica by weight per polymorph

Quick Method Selector — Which silica test do you need?

OSHA compliance monitoring for workers?
→ XRD (NIOSH 7500 / OSHA ID-142)
Simple dust profile, quartz only environment?
→ FTIR (NIOSH 7602) — faster, lower cost
Need full worker exposure profile?
→ NIOSH 0600 (dust) + NIOSH 7500 (XRD)
Foundry, high-temp, or unknown minerals?
→ XRD only — FTIR misses cristobalite/tridymite
Characterize raw material before work begins?
→ Bulk XRD — % silica by weight
Validate wet suppression or LEV system?
→ Pre/post-control XRD personal monitoring
Crystalline Silica Minerals

Three Regulated Silica Polymorphs We Identify

Not all silica is the same. Polymorph identity matters for regulatory treatment, health risk assessment, and which analytical method reliably detects each form. XRD (NIOSH 7500) identifies all three — FTIR (NIOSH 7602) detects quartz only.

Quartz
α-Quartz · Most Common Form
OSHA Regulated ~95% of Exposures
The most abundant form of crystalline silica in the earth's crust. Found in sand, concrete, mortar, granite, sandstone, slate, and most silica-bearing construction materials. The primary cause of occupational silicosis. Both NIOSH 7500 (XRD) and NIOSH 7602 (FTIR) detect and quantify quartz. The OSHA PEL of 50 µg/m³ applies to quartz as well as the other polymorphs.
Cristobalite
High-temperature silica polymorph
OSHA Regulated High-Temp Processes
Forms when quartz is heated above 1,470°C — found in foundry sand, refractory ceramics, volcanic soils, and some calcined diatomaceous earth products. Considered more biologically reactive than quartz and carries a higher potency factor per unit mass. FTIR does not reliably detect cristobalite — XRD is required. Disproportionately hazardous in foundry and kiln environments.
Tridymite
Metastable high-temperature polymorph
OSHA Regulated Kiln & Smelter Environments
The rarest of the three common polymorphs. Forms at extremely high temperatures (above 870°C) in some kilns, smelters, and volcanic environments. Less commonly encountered in routine occupational monitoring but OSHA-regulated at the same PEL. XRD is the only reliable method for tridymite quantification. Reported alongside quartz and cristobalite in every AGT Labs XRD silica report.
Lab Accreditation ISO/IEC 17025:2017
IH Lab Accreditation AIHA LAP · ID: LAP-101470
Environmental Testing PJLA Accredited
Lab Location Houston TX · In-House Analysis
Report Deliverables

Every Method, Every Standard, Every Deliverable

No surprises in your silica testing report. Here's exactly what each analysis returns — methods, media, and deliverables side by side.

Analysis Type Method / Standard Sample Media Report Deliverable Rush?
Crystalline Silica — XRDNIOSH 7500 / OSHA ID-14237mm PVC filter (5.0 µm) + cycloneµg/sample quartz + cristobalite + tridymite · TWA · PEL comparisonYes
Crystalline Silica — FTIRNIOSH 760237mm PVC filter (5.0 µm) + cycloneµg/sample quartz · TWA · PEL comparisonLimited
Respirable Dust GravimetricNIOSH 0600Pre-weighed PVC filter + cyclonemg/m³ total respirable dust · OSHA PEL comparisonYes
Total Dust Gravimetric (PNOR)NIOSH 0500Pre-weighed PVC filter (no cyclone)mg/m³ particulate not otherwise regulatedYes
Dual: Dust + XRD SilicaNIOSH 0600 + NIOSH 7500Single pre-weighed PVC filter + cyclonemg/m³ respirable dust + µg/m³ silica per polymorph · both PEL comparisonsYes
Bulk Silica ContentXRD / NIOSH 7500 (Mod)Bulk material (powder, chunk)% crystalline silica by weight · polymorph breakdownCall
Lab Logistics

Turnaround Times & Free Sampling Media

Every rush option and kit detail — clearly laid out before you submit your first sample.

Turnaround OptionTimelineSurcharge
Standard Analysis7+ Business DaysNo Surcharge
4-Day Rush4 Business Days+25%
3-Day Rush3 Business Days+50%
2-Day Rush2 Business Days+75%
1-Day Rush1 Business Day+100%
Samples received before 2:00 PM CST logged same day. Call (713) 453-6090 to confirm rush capacity for large silica batches. Dual dust+silica (NIOSH 0600 + 7500) available at combined pricing.

Sampling Media & Equipment

  • Pre-weighed 37mm PVC filters (5.0 µm pore size)
  • Matched weight filter pairs for gravimetric QA
  • Dorr-Oliver nylon cyclones (1.7 L/min)
  • SKC aluminum cyclones (2.5 L/min)
  • Calibrated personal air sampling pumps — loaner program
  • Field blank filters (10% of batch, pre-labeled)
  • Pre-paid UPS return shipping label
  • Industrial Hygiene Chain of Custody form
Download IH COC Form
Field Protocol Reference

Silica Sampling Field Requirements

Silica testing is unforgiving of poor field protocol. Using the wrong flow rate for your specific cyclone will invalidate the particle size cut-point, rendering the data useless for OSHA compliance. Full reference: IH Sampling & Analysis Guide.

Cyclone Flow Rates
Dorr-Oliver (Nylon)
1.7 L/min exactly. Most common cyclone in US field work. Flow must be maintained within ±5% throughout the shift. Calibrate before and after sampling with the cyclone in-line.
SKC Aluminum
2.5 L/min exactly. Higher flow rate — do not substitute Dorr-Oliver flow rate for this cyclone. Document the cyclone make/model on the COC or results cannot be validated.
BGI GS-3
2.75 L/min. Less common but fully NIOSH-validated. Record exact cyclone model and serial number on COC.
Calibration
Calibrate before and after each sampling day with the complete sampling train (cyclone + cassette + filter) in-line using a primary standard. Record both readings on COC.
Filter & Volume Requirements
Filter media
37mm PVC filter, 5.0 µm pore size ONLY. MCE filters used for asbestos and metals are incompatible — they cannot be analyzed by XRD or FTIR for silica.
Sample volume
Minimum 400–1,000 liters to reach the method LOD relative to the Action Level (25 µg/m³). Full-shift sampling (400–960 L at 1.7 L/min) is strongly recommended for OSHA compliance documentation.
Filter overloading
If visible dust is heavy, cap volume at 200 L to prevent filter overloading which prevents accurate gravimetric weighing and XRD analysis. Note loading concern on COC.
Field blanks
Submit at least two field blanks per sampling event, or 10% of the total sample count (whichever is greater). Open cassette at sampling location for 30 seconds, seal immediately. Label as "field blank" on COC.
Dual Dust + Silica Protocol
Pre-weighing
For combined dust + silica analysis, filters must be pre-weighed by the lab before shipping to you. Do not use field-purchased filters — they may not be gravimetrically tared to sufficient precision.
Cassette handling
After sampling, keep the cassette upright. Avoid dropping or shaking — dislodged dust that falls to cassette walls will NOT be captured in the gravimetric weighing, artificially lowering the result.
Transportation
Ship in the cassette shipping container provided. Do not remove filters from cassettes in the field. The lab performs all filter handling under controlled conditions.
COC fields
Record: cyclone model, pre-/post-calibration flow rates, start/stop times, calculated total volume (L), worker name, task performed, and any engineering controls in use.
Shipping & Drop-Off
Lab address
10200 East Freeway, Suite 101, Houston TX 77029. Before 2:00 PM CST for same-day log-in. Call (713) 453-6090.
Carrier
UPS Ground preferred. Pre-paid return label included in kit. For large batches, call ahead — rush XRD slots are capacity-limited per day.
Temperature
No special temperature requirements for PVC silica filters. Do not ship near strong solvents or acids — filter degradation will affect gravimetric accuracy.
COC completion
All COC fields must be completed before submission. Incomplete volume information prevents TWA calculation — the report cannot be used for OSHA compliance without a valid volume.
Submission Workflow

From Sample Collection to Final Report

1

Request Kit & Pumps

Contact us to request pre-weighed PVC filters, cyclones, and loaner pumps. We ship nationwide.

2

Collect Air Samples

Deploy pumps on workers using exact flow rates required by your specific cyclone type.

3

Ship to Lab

Keep cassettes upright. Complete COC with flow rates and total volumes. Ship to our Houston lab.

4

Gravimetric & XRD

We weigh the filters for total respirable dust, then perform XRD analysis for specific silica polymorphs.

5

Compliance Report

Receive your detailed report comparing detected concentrations against OSHA PELs via our secure portal.

Standards & Regulatory Context

OSHA Silica Regulations Explained

The 2016 OSHA Silica Rule drastically lowered permissible exposure limits. Here is how our testing helps you comply.

OSHA 29 CFR 1926.1153 — Construction
Requires employers to limit exposure to the PEL of 50 µg/m³. Employers must either strictly follow the engineering controls in "Table 1" or conduct objective air monitoring to prove exposures are below the PEL.
OSHA 29 CFR 1910.1053 — General Industry
Applies to manufacturing, maritime, and hydraulic fracturing. Unlike construction, there is no "Table 1" safe harbor. General industry employers MUST conduct baseline exposure assessments via air testing.
NIOSH REL — Recommended Exposure Limit
NIOSH recommends a REL of 50 µg/m³ for respirable quartz. For cristobalite, NIOSH recommends a more conservative limit of 25 µg/m³ due to its higher biological potency. Our XRD analysis separately quantifies each polymorph.
MSHA — Mining Applications
The Mine Safety and Health Administration enforces silica exposure limits in mining. MSHA uses NIOSH 7500 (XRD) for compliance monitoring. AGT Labs' ISO/IEC 17025 accredited XRD results are accepted for MSHA compliance.
ISO/IEC 17025 — Lab Accreditation
Our laboratory accreditation under ISO/IEC 17025:2017 through AIHA LAP LLC certifies that every silica analysis — sample preparation, XRD diffraction, quantification, and reporting — is performed under validated, traceable procedures.
Medical Surveillance Trigger
Under both 1910.1053 and 1926.1153, workers exposed to RCS at or above the Action Level (25 µg/m³) for 30 or more days per year must be enrolled in a medical surveillance program including chest X-rays and spirometry.
Industries & Clients

Who Relies on Our Crystalline Silica Testing Lab

Construction & Concrete Work

GCs, subcontractors, and concrete cutting specialists — silica monitoring for OSHA 1926.1153 Table 1 alternatives, saw cutting, coring, grinding, and jackhammering operations on Texas and Gulf Coast projects.

Oil & Gas / Hydraulic Fracturing

Frac sand handling, blending, and pumping operations generate some of the highest silica exposures measured in any industry. OSHA 1910.1053 baseline and periodic monitoring for well-site supervisors, blender operators, and sand transfer crews.

Foundries & Metal Casting

Foundry operations using silica sand molds generate cristobalite and tridymite — polymorphs that FTIR misses. XRD (NIOSH 7500) with full polymorph reporting is essential for OSHA 1910.1053 compliance in iron, steel, and aluminum foundry environments.

Abrasive Blasting Operations

Sand blasting, shot blasting, and surface prep contractors — Texas OSHA-regulated environments where exposures can exceed the PEL by 10–50× without proper controls. Task-specific and personal monitoring for compliance and engineering control validation.

Industrial Hygiene Consultants

Environmental and IH consulting firms across Texas, Gulf Coast, and nationwide — bulk sample and air monitoring analysis with accredited XRD results, complete with TWA calculations and OSHA PEL comparisons formatted for client reports and citations defense.

Ceramics, Glass & Mining

Ceramics and glass manufacturing (cristobalite and tridymite risk), stone quarrying, and surface mining — MSHA and OSHA 1910.1053 compliance monitoring. Bulk silica content characterization for raw materials and SDS documentation.

Client Support

Silica Testing — Frequently Asked Questions

What is the OSHA PEL for respirable crystalline silica?
The OSHA Permissible Exposure Limit (PEL) for respirable crystalline silica is 50 µg/m³ as an 8-hour time-weighted average (TWA). The OSHA Action Level (AL) is 25 µg/m³.
What methods does your crystalline silica testing lab use?
AGT Labs primarily uses X-Ray Diffraction (XRD) following NIOSH 7500 and OSHA ID-142 methodologies, which is considered the gold standard for distinguishing silica polymorphs (quartz, cristobalite, tridymite). We also offer Infrared Spectroscopy (FTIR) following NIOSH 7602 upon request.
Do you provide cyclones and sampling pumps?
Yes. With 5 business days' notice, we provide pre-weighed PVC filters (typically 37mm, 5.0 µm), sampling cassettes, and aluminum or nylon cyclones. We also offer a pump loaner program equipped with calibrated personal air sampling pumps for qualifying clients.
What is the required air volume for silica sampling?
Required volume depends on the cyclone used to achieve the necessary limit of detection. Typically, a minimum of 400 to 1,000 liters is recommended. Flow rates vary strictly by cyclone model (e.g., Dorr-Oliver Nylon at 1.7 L/min, SKC Aluminum at 2.5 L/min).
When is silica air testing legally required?
Under OSHA 1926.1153 (Construction) and 1910.1053 (General Industry), employers must assess employee exposure to silica if it may be at or above the Action Level of 25 µg/m³. For construction, if you are not fully implementing the engineering controls specified in 'Table 1', objective air monitoring data is legally required.
Can you analyze both respirable dust and silica from the same filter?
Yes. We can perform a gravimetric analysis for total respirable dust (NIOSH 0600) and then subsequently analyze that exact same PVC filter for crystalline silica via XRD (NIOSH 7500). This provides a complete exposure profile from a single worker sample.
What turnaround times do you offer for silica testing?
Standard results are delivered in 7+ business days with no surcharge. Rush options are available: 4-day (+25%), 3-day (+50%), 2-day (+75%), and 1-day (+100%). Samples received before 2 PM CST are logged on the same day.
What is the difference between Quartz, Cristobalite, and Tridymite?
These are the three main crystalline polymorphs of silica. Quartz is the most common, found in sand, stone, and concrete. Cristobalite and Tridymite are formed when quartz is subjected to high temperatures (like in foundries or kilns). Our XRD methods can detect and quantify all three distinct forms.

Ready to Partner with a Certified Crystalline Silica Testing Lab?

AIHA LAP accredited · XRD & FTIR Methods · Pump Loaner Program · Rush TAT available · Houston TX

Get a Quote Call (713) 453-6090
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