February 21, 2014

Ms. Lisa Swab
Quality Assurance Manager
Galson Laboratories
6601 Kirkville Road
East Syracuse, NY 13057

Dear Ms. Swab,

Thank you for your letter received by the Occupational Safety and Health Administration's (OSHA), Directorate of Enforcement Programs, on October 17, 2013. Your letter is a follow up to an earlier conversation between Mr. Bill Walsh of Galson Laboratories and staff from our Office of Health Enforcement regarding a question from Mr. Walsh about the air sampling and field extraction procedure described in the OSHA Instruction, National Emphasis Program - Occupational Exposure to Isocyanates, CPL 03-00-017 (Isocyanates NEP). Mr. Walsh's question is paraphrased below. This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any question not detailed in your original correspondence.

Question: If a commercial laboratory receives an air sample from a client for isocyanate analysis and the sample was not field extracted (desorbed) at the time it was collected, as described in the National Emphasis Program - Occupational Exposure to Isocyanates, CPL 03-00-017, what will OSHA's position be regarding the validity of the sample?

Response: The air sampling and field extraction method described in the Isocyanates NEP represents enforcement and procedural guidance for OSHA compliance staff to follow when collecting air samples during an inspection related to worker exposure to isocyanates. As stated in the Isocyanates NEP, the purpose of the field extraction is to enhance the recovery of highly reactive isocyanates that are collected on OSHA's air samples. This internal guidance was not intended to impose a requirement for employers regarding their own sample collection. An employer may choose an alternative air sampling method, but the method should provide an accurate measurement of worker exposure to isocyanates.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA requirements are set by statute, standards, and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at http://www.osha.gov.

If you have any further questions, please feel free to contact the Office of Health Enforcement at (202) 693-2190.

Sincerely,

Thomas Galassi, Director
Directorate of Enforcement Programs