Note: | You can use Steps three through six of this process to create a written description of the procedure used for obtaining representative employee exposure monitoring results, which is a requirement in Exposure records, WAC 296-855-20070. |
Exemption: | 1. You can skip Steps four through seven if you have documentation conclusively demonstrating that employee exposure for a particular material and the operation where it's used, cannot exceed the AL or STEL during any conditions reasonably anticipated. |
2. Such documentation can be based on observations, data, calculations, and previous air monitoring results. Previous air monitoring results: | |
a. Must meet the accuracy required by Step five. | |
b. May be from outside sources, such as industry or labor studies. | |
c. Must be based on data that represents conditions being evaluated in your workplace. |
Step five: | Determine how you will obtain accurate employee exposure monitoring results. Select and use an air monitoring method with a confidence level of ninety-five percent, that's accurate to: |
• ±twenty-five percent when concentrations are potentially above the AL or eight-hour time-weighted average of one part per million (ppm). | |
• ±thirty-five percent when concentrations are potentially above the AL of 0.5 ppm or the STEL of five ppm. |
Note: | Here are examples of air monitoring methods that meet this accuracy requirement: |
1. OSHA Method thirty found by going to: http://www.osha.gov/dts/sltc/methods/toc.html. | |
2. NIOSH Method thirty eight hundred found by going to: http://www.cdc.gov./niosh/homepage.html and linking to the NIOSH Manual of analytical methods. |
Step six: | Obtain employee monitoring results by collecting air samples representing employees identified in Steps three and four. |
• Collect STEL samples for employees and operations selected in Step three. | |
• Collect samples representing the eight-hour exposure, for at least one shift, for each employee selected in Step four. | |
• Make sure samples are collected from each selected employee's breathing zone. |
Note: | 1. You may use any sampling method that meets the accuracy specified in Step five. Examples of these methods include: |
a. Real-time monitors that provide immediate exposure monitoring results. | |
b. Equipment that collects samples that are sent to a laboratory for analysis. | |
2. The following are examples of methods for collecting samples representative of eight-hour exposures. | |
a. Collect one or more continuous samples, such as a single eight-hour sample or four two-hour samples. | |
b. Take a minimum of five brief samples, such as five fifteen-minute samples, during a work shift at randomly selected times. | |
3. For work shifts longer than eight hours, monitor the continuous eight-hour portion of the shift expected to have the highest average exposure concentration. |
Step seven: | Have the samples you collected analyzed to obtain monitoring results for eight-hour and STEL exposures. |
• Determine if employee exposure monitoring results are above or below the following values: | |
– Eight-hour time-weighted average (TWA8) of one ppm. | |
– Fifteen-minute short-term exposure limit (STEL) of five ppm. | |
– Eight-hour action level (AL) of 0.5 ppm. |
Note: | You may contact your local WISHA consultant for help: |
1. Interpreting data or other information. | |
2. Determining eight-hour or fifteen-minute employee exposure monitoring results. |