Communications with Your Industrial Hygiene (IH) Laboratory: Before You Sample, When You Submit Your Samples for Analysis, and After You Get Your Results.

-NOTE- The information in this document is provided as an example. It should not be construed as representing OSHA requirements or policy.

What information should we exchange?

Good communication with your IH laboratory is important to get the right treatment for your samples and to get the most reliable results. As a consumer of analytical services, you need to address the whole analytical "life-cycle."

A. Laboratory Selection. Twice annually, the AIHA publishes the geographical listing of 300+ accredited industrial hygiene laboratories along with any purchased advertisements describing the services. Of these approximately 70 are accredited to analyze crystalline silica see, AIHA Accredited Laboratories--September 1996 (Address list used in D.K. Smith's survey of laboratories accredited to perform silica analyses). Currently AIHA-accredited labs appear in the April and September issues of the AIHA Journal and in flyers for targeted marketing of such services. The following items represent good science and include some of the accreditation requirements.

  1. Licensed and certified as needed in state.
  2. Qualified and trained personnel performing the analyses.
  3. Versed in the analytical method you need for your sample matrix.
  4. Provides a list of interferences for the analytical method that will be used.
  5. Quality Control program in place.
    a. Calibration standard reference materials traceable to NIST or NIOSH.
    b. Quality Control or Quality Assurance samples prepared and analyzed along with regular samples.
    c. Quality Control results charted. Policy for QCs that go out of control. Are results released regardless of QC results?
    d. Calibration check samples that bracket the sample results (re)analyzed along with regular samples.
    e. Written analytical procedure adhered to (modified only for good analytical reason.)
    f. Maintenance program.
    g. Turn-around time meets your time constraints.
    h. Data provided laboratory and results are secure and confidential. Trade secrets are not accessible.

B. Method Sampling Requirements.

  1. Proper leak-tested cyclone.
  2. Correct sampling medium.
  3. Calibrated pump with cyclone and assembled cassette in place.

C. Sampling.

  1. Consult the list of interferences provided by the laboratory. Note whether these interferences are known to occur in the worksite to be sampled.
  2. Collect air sample in the employee's breathing zone.
  3. Collect any bulks requiring analysis or provided for lab use if needed. The analysis of your manufactured product(s) may be needed in supporting the Hazard Communication (HAZCOM) standard. When the quartz content exceeds 0.1% quartz a MSDS may be required. Products containing low levels of quartz may pose a difficult analytical problem because it is often difficult to measure quartz content down to the 0.1% quartz level required for HAZCOM compliance. Different methods (and perhaps a different laboratory) than used for air samples may be needed for bulk material. Bulk analyses may require methods such as microscopy (refractive index and birefringence) and thermal analysis (heat released at the beta to alpha quartz transition near 573 deg. C). Manufactured articles, such as tiles and bricks, require MSDSs if the potential exists to produce respirable dust in normal use. Normal use of these articles in construction includes sawing. Prudent sawing requires precautions such as the use of wet sawing techniques and methods of cleanup that avoid creating suspended dust. It has been ruled that, logically, an employee cannot take the proper precautions to avoid exposure of self and others to respirable crystalline silica if that information is not provided.
  4. Ship according to laboratory's procedure including a list of any interferences you think may be present in the air samples.

D. Analytical Method is Performed at the Laboratory.

  1. Know which analytical methodology is being used. Its advantages and disadvantages.
  2. Brief OSHA Comparisons of Analytical Methods for Crystalline Silica (Table).
  3. MSHA/Bureau of Mines Comparison of Methods used to Detect Quartz in a Sample (Table 3 excerpted from Page 34 of "Crystalline Silica Primer."

E. Results Reported

  1. What method does the laboratory use.
  2. Are the results confirmed before releasing results to the customer? For example, if the lab does not confirm a result based on the most intense X-ray diffraction peak of quartz, would the lab could report mica or graphite contaminants as quartz?
  3. Are problems with QCs resolved before releasing results to the customer?
  4. What is the laboratory's estimate of the sampling and analytical error (SAE)?
  5. What is the laboratory's qualitative and quantitative detection limits (in % and microgram units)?
  6. For instrumental methods that can provide a graphic portrayal of the scan as in XRD, IR, and FTIR, are scans of your samples saved with the data?
  7. Can the method used reveal unknown interferences?
  8. What actions are taken when an interference is observed?
  9. For instruments that can provide scan peak data as in XRD, IR, and FTIR, are integrated (summed) peak areas or peak height instrument responses used to determine the amount of analyte present in the samples?
  10. Are scans, calculations, and results of the analyst checked independently by someone else trained on the method?
  11. How are results presented to the customer? Is the current laboratory SAE and DLs provided? Are result descriptors such as "less than" and "less than or equal to" explained adequately? Do these descriptors describe the qualitative or quantitative detection limit, lack of confirmation, or a "conservative" worst case result?