Respirators, protective clothing, decontamination facilities and medical examinations are required by OSHA regulations for working with asbestos-containing material in many situations. However, the Construction Industry Standard (29CFR1926.1101) allows you to dispense with these measures and still remain in compliance if a specific process is followed. This process is called the Negative Exposure Assessment.
Not all O&M work is eligible for an NEA, including Class III work that disturbs thermal system insulation or surfacing material. The process is most effective with non-friable materials such as floor tile, siding and other asbestos-cement products, gaskets, etc.
An employer still has the option to use these precautions even if an NEA is in effect.
How do I use a Negative Exposure Assessment?
The process is shown in the flow chart on the right. It begins with an Initial Exposure Assessment (IEA) in which you first demonstrate that the work being performed does not exceed either of the OSHA Permissible Exposure Limits. Having done that, the competent person compares the “current job” to the IEA and determines that
1) The work practices and materials for the current job “closely resembles” those during the IEA
2) The workers for the current job have been trained on these work practices and materials
3) Worker exposure has been monitored within the past year and is in compliance with the PELs
If all three of these conditions are met, the competent person certifies that an NEA applies to the current job.
Who is the competent person?
Under the OSHA Construction Industry standards, the competent person is responsible for health and safety at the job site and has the authority to take corrective action. The competent person is usually a foreman or supervisor.
The NEA process is described in detail in the audio-visual program Asbestos Negative Exposure Assessments and Competent Person Training, available from Environment-i-media, Inc. in Powerpoint and VHS videotape. This program provides all the information you will need to do your own testing, including air sampling for worker exposure, to conduct the Initial Exposure Assessment and annual updates.The Powerpoint version includes software for the air sampling calculations and forms in MS Word for certifying that an NEA applies to the work.
The Initial Exposure Assessment is performed in a negative pressure enclosure by workers wearing respirators and protective clothing. The annual updates can be done without these precautions because you know from previous testing that the PELs are not expected to be exceeded.
Two sampling pumps and filter cassettes are worn for assessing worker exposure. One cassette remains on for the duration of the test (usually 2 - 3 hours) and provides the sample to compare to the 0.1 f/cc full-shift PEL. The other cassette is changed every 30 minutes and measures compliance with the 1.0 f/cc Excursion Limit.
How can you help me with NEAs?
I have been doing Negative Exposure Assessments since shortly after these regulations went into effect and have refined the process of conducting the Initial Exposure Assessment and annual updates of the exposure monitoring data. I can provide assistance tailored to your needs and available resources.
I can train your staff members or consultants to perform the testing and calculations, and also train the workers who will be doing the “current job” when required. At least one of your workers, preferably a supervisor, should receive training as a competent person, and I can do that as well. My experience has shown that this additional training takes so little time that it is worth giving it to all workers who might do a job to which an NEA applies, even if they are not in a supervisory position.
I can also conduct the testing for the IEA and annual updates. This will require that I become familiar with your work practices and the asbestos-containing materials to which they apply. I will then design a test plan, oversee the preparation of the test site at your facility, direct the worker(s) during the tests and take all air samples. I will make arrangements to have the samples analyzed by Phase Contrast Microscopy. For the IEA, you will be responsible for obtaining (and paying for) the services of an abatement contractor to provide the worker(s) unless someone on your own staff is qualified to do the work.
After the testing is complete, I will calculate the employee exposure for compliance with both OSHA PELs and also calculate the 95% Upper Confidence Limit, which is a statistical measure of the chance of exceeding the limits. I do not recommend relying on an NEA unless these calculated values are well below the PELs (see chart on right). Finally, I will prepare a template for your competent person to use when certifying that an NEA applies to a current job.
Initial Exposure Assessment |
Testing for annual update |
Training for Class III work subject to an NEA requires at least four hours according to an OSHA "clarification." It must include a hands-on exercise using the asbestos-containing materials (or simulated materials) and work practices the employee will use on the job. The competent person certifies that the most recent testing has been done within the past twelve months.
How long does it take? How much does it cost?
A properly-done NEA requires more than taking one or two air samples. For the statistical confidence that OSHA requires to assure than the PELs will not be exceeded, the number of air samples shown on the right is recommended. In other words, a full day of testing is needed for each material and each work practice being evaluated. For the IEA, allow time for set-up and tear-down of the negative pressure enclosure.
Testing is labor-intensive and manpower costs far exceed those of equipment, supplies and laboratory services. The test director must be present throughout the test to control the pace of the work as well as taking the air samples.
If you will call me and describe the work for which you are considering an NEA, I will provide an estimate of my time and charges for preparing the test plan, directing the tests, having the samples analyzed and preparing the required documentation. I will also quote you my fees for training your workers and competent persons as needed to use the NEA.
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