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Subchapter 7. General Industry Safety Orders
Group 16. Control of Hazardous Substances
Article 109. Hazardous Substances and Processes

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§5197. Appendix A. Diacetyl Sampling and Analytical Protocol (Mandatory)

This appendix establishes requirements for sampling protocols and the procedure for taking and analyzing air samples for diacetyl including quality control procedures that must be implemented by the person conducting the sampling and by the laboratories performing the analysis. All employers who are required to conduct air monitoring under subsection (c) of this section are required to utilize analytical laboratories that use this procedure, or an equivalent method, for collecting and analyzing samples.

(a) Sampling Protocols.

(1) Personal Samples

(A) 8-hour time-weighted average. Due to the limited sampling time for the OSHA Method, eight-hour time-weighted average (TWA) exposure estimates must be constructed for each employee. Collect sequential samples as recommended by the OSHA Method or an equivalent method for periods no longer than 180 minutes per sample to cover the full work-shift of the employee. For an eight-hour work shift, this will include the collection of a minimum of three dual-tube samples for each employee unless the full duration of the employee's exposure to diacetyl or diacetyl-containing flavorings or food products is less than the full work shift. Cleaning and sanitizing activities must be sampled separately from production processes.

(B) Short-term exposure. Collect short term exposure samples as recommended by the OSHA Method or an equivalent method, to represent the highest likely potential 15 minute exposure(s) for each process. Examples of activities that should be monitored for short term exposures include periods of a process in which tanks or containers are opened, filled, unloaded or cleaned; where process equipment is opened; and where diacetyl or diacetyl-containing flavorings or food products are heated or sprayed.

(2) Monitoring for verification of enclosed processes or to determine whether respirators need not be required in a regulated area.

(A) Eight-hour TWA and short term exposure personal samples, in accordance with section (a)(1), shall be collected for each shift and each job classification for employees in the area where process vessels or operations are located.

(B) Area samples shall also be collected by the placement of samplers in the areas the program reviewer determines likely to have the highest levels of airborne diacetyl. A minimum of four locations shall be sampled for each process. The employer shall record the nature of and location of the process being sampled, the location of the sampler, the time and date of the sampling, the measured air concentration from the dual-tube samples, the method RQL for the sample, and evidence of its accuracy, including the ambient temperature and humidity.

(C) If any individual sample collected in the course of testing to verify that a system is enclosed is determined to contain diacetyl above the OSHA RQL, then the process shall not be deemed enclosed. If any individual sample collected in the course of testing to determine if respirator use must be required in a regulated area is determined to contain diacetyl above the OSHA RQL, then respirator use shall be required in the regulated area.

(3) This sampling protocol cannot be used as the sole basis for respirator selection in a regulated area if diacetyl-containing powders are used in the regulated area.

(b) Sampling Procedure.

(1) Samples shall be collected using a personal sampling pump calibrated prior to and after each day of sampling, with a representative sampling train attached between the pump and the calibration device, to within ± 5% of the recommended flow rate specified in the OSHA Method or in the equivalent method selected. In the OSHA Method the tubes must be wrapped in aluminum foil (or a special tube cover used) to protect the sampling devices from light, especially sunlight, during sampling, storage and handling.

(2) Review and follow the sampling procedures in the OSHA Method or in the equivalent method selected. The sampling procedure shall also include the following:

(A) Record sample air volumes (liters), sampling time (minutes) and sampling rate (mL/min) for each sample, along with any potential interference(s) on a sample summary form.

(B) Personal samples shall be taken in the “breathing zone” of the employee (i.e., attached near the collar or lapel near the worker's face). The sampler inlet shall be located outside of the respirator, and outside of any personal protective equipment or clothing, and there shall be no impediment to airflow into the sampler.

(C) Each set of samples taken will include 10% field blanks or a minimum of one field blank, whichever is greater. These blanks must come from the same lot as the tubes used for sample collection. Handle the blank sample in the same manner as the other samples except draw no air through it. A set consists of any sample or group of samples for which an evaluation for this standard must be made. Any samples represented by a field blank having an excess of the limit of detection (LOD) of the method being used shall be rejected, and additional sampling conducted to represent that exposure.

(c) Analytical Procedures.

(1) All samples shall be analyzed by a laboratory accredited in accordance with the program of the American Association for Laboratory Accreditation, the American Industrial Hygiene Association (AIHA) Laboratory Accreditation Programs, LLC or other International Laboratory Accreditation Cooperation mutual recognition signatory.

(2) The laboratory shall analyze all samples using the OSHA Method or an equivalent method.

(3) Each sampling tube shall be analyzed separately, and the results recorded. For each sampling tube, the employer shall ensure that the record includes the date, time, location and identity of the process being sampled, the name and employee identifier of the employee being sampled, the employee's job classification, the specific job duties of the employee, and the mass collected from the tube. The records for each dual-tube sample shall include the measured air concentration from the dual-tube samples, the method RQL for the sample, field evidence of its accuracy, including ambient temperature and humidity, and any comments from the analytical laboratory pertaining to the accuracy of the sample. The record for short term exposure samples shall also identify the specific activity being sampled.

(4) All laboratories as part of their accreditation shall participate in an appropriate national sample testing scheme such as the Proficiency Analytical Testing Program (PAT) for organics that is sponsored by the AIHA.

Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


1. New Appendix A filed 11-2-2010; operative 12-2-2010 (Register 2010, No. 45).

2. Amendment of subsections (c)(1) and (c)(4) filed 7-1-2013; operative 10-1-2013 (Register 2013, No. 27).

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