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Be sure your sampling meets OSHA’s requirements

Sampling is more than just slapping a pump on an employee to see if their exposures exceed legal limits.  The expectations of sampling strategy and recordkeeping are best exemplified in OSHA’s expanded standards.  First, we’ll discuss general best sampling strategies and then we will use the Methylene Chloride standard, 1910.1052, to demonstrate OSHA’s expectations for sampling and recordkeeping.

Sampling without a carefully thought-out strategy often results in misleading data, not to mention a waste of time and money.  The sampling equipment, sampling media, and sample analysis must meet or exceed accuracy and precision requirements, usually denoted as the Sampling and Analytical Error (SAE).  There are many purposes for sampling such as

  • Testing the efficiency and effectiveness of engineering controls.
  • Identifying high exposure areas or tasks that need to be controlled.
  • Assessments of employee exposure.

Environmental conditions on the sampling day can affect sampling results enough to turn an over exposure into a compliant exposure, or vice-versa.  Here are some effects of different environmental conditions on air contaminant generation:

  • Vapor pressures for solvents tend to increase with increasing temperatures increasing exposures
  • Facilities with large doors and windows that open tend to have them closed in the winter keeping exposures within the work areas.
  • Facilities with large doors and windows tend to have them open in the summer when cross drafts can defeat the capture velocity of local and general exhaust ventilation creating unexpected eddies and pockets of high air concentration of chemical vapors or gases.
  • Hot conditions during the day can be cool to cold conditions at night, windows and doors that were open for the first shift are closed for the second shift resulting in a requirement to sample both shifts for employee exposures.

Strategy always relates to employee exposure(s) and how to keep employees healthy and working.  Unlike China, America does not have unlimited people seeking employment in order not to starve.  Since the baby boomers retired, the birth rate decline and our public education system pointing everyone to college, getting and keeping quality employees has become as much of a challenge to businesses as broken supply chains, inflation and tightening regulations.  Strategy starts with the purpose for sampling followed by the decision to conduct personal or area sampling, or both. 

Personal sampling requires careful selection of which employees should wear the sampling equipment:

  • All employees suspected of having sufficient exposure to air contaminants or to noise that it can be reasonably expected to exceed the exposure limit should be sampled. Under certain conditions sampling can be considered to represent other employee exposures, such as on different shifts or performing similar tasks in similar conditions.  This always requires careful documentation to show that:
    • the work practices the same for both/all shifts.
    • the employees work the same distance from the exposure source.
  • Where exposures vary slightly you must document that the representative sampling was done for the highest exposure conditions.
  • If you are sampling for comparison to an 8-hour Time Weighted Average (TWA) make sure you select the 8-hours with for the highest exposures. If it is at the beginning of the shift and the shift starts at 5:30AM then you need to get there at 5AM to be ready to put the equipment on the employees and document start times.  I recommend using two obnoxious alarms greater than arm’s length from the bed.
  • If you are sampling for something with a standard like noise you can sample for more than 8 hours and then calculate the representative Action Level for comparison.
  • Methylene Chloride has a STEL, a Short-Term Exposure Limit, which is the average exposure over 15 minutes. The 15 minutes selected should be for a task or time when the employee’s exposure is expected to be the highest.

Area sampling is usually conducted when employees are only intermittently exposed to an air or noise contaminant.  If the results come out over the limit you can calculate the maximum time of exposure to keep employee exposures below the limit.  Area sampling is also used to check engineering controls.  The placement of the sampling equipment is very important and diagrams or pictures should be used to show where it was placed for future reference.

Naturally, production conditions have a profound effect on employee exposures I always recommend sampling under the highest exposure condition, if you are under then you’re under during normal working conditions.  However, few of my clients opt for this safe guard.  For companies that do piece work for different customers the work floor, raw products, and production processes can vary quite a bit.  A careful documentation of the conditions on the sampling day allows the client to compare the current conditions to those on the sampling day to see if there is potential for greater, equal, or less exposure to chemical or noise hazards. This is why the person conducting the sampling must remain onsite and make frequent rounds to observe the employee’s actions and distance related to the exposure source.

Recordkeeping is required, even if the employee and/or conditions are below exposure limits, by 1910.1020.  Each of my reports include the following information to assist my clients in complying with this standard:

“This document is an employee exposure record as defined by OSHA’s 1910.1020 standard, Access to Employee Exposure and Medical Records.  It is highly recommended that you read this standard as it pertains to more conditions found in the average workplace than will be described below.

Employee exposure records include:

  1. Sampling results: personal, area, grab, wipe, and other forms of sampling.
  2. The sampling collection and analytical methods. (The attached lab results and calibration data.)
  3. Any calculations or other background data relevant to the interpretation of the results.
  4. Safety Data Sheets.

1910.1020(d)(1)(ii) Employee exposure records. Each employee exposure record shall be preserved and maintained for at least thirty (30) years, except that:

1910.1020(d)(1)(ii)(A) Background data to environmental (workplace) monitoring [AKA Area sampling] or measuring, such as laboratory reports and worksheets, need only be retained for one (1) year as long as the

  • sampling results,
  • the collection methodology (sampling plan),
  • a description of the analytical and mathematical methods used, and a summary of other background data relevant to interpretation of the results obtained, are retained for at least thirty (30) years

This report is designed to meet these requirements.  So, just keep this report where you can put your hands on it for 30 years.

Whenever an employer has exposure or medical records the requirements of this standard are applicable.  Employers are required to provide employees training, initially and annually thereafter, by paragraph (g) of 1910.1020.  The training topics shall include:

  1. The existence, location, and availability of any records covered by this standard.
  2. The person responsible for maintaining and providing access to records; and
  3. Each employee’s rights of access to these records.

The Access to Employee Exposure and Medical Records standard requires you to keep a copy of the 1910.1020 and its appendices, and provide copies, upon request, to employees. You are also required to distribute to current employees any informational materials concerning this section which are made available to the you by the Assistant Secretary of Labor for Occupational Safety and Health.

Personal employee exposure records are required to be retained by the employer for 30 years and made available to current or former employees, and/or their designated representatives, upon request. 

This report can also be used to recognize changes to processes, conditions, or work areas sufficient to make the data and conclusions in the report no longer representative of employee exposures.  Where the changes have potential to increase employee exposures above exposure limits actions should be taken to conduct further sampling.”

The general information used above came from my classes at the University of Michigan where I studied Industrial Health.  Now we’ll go over how an expanded standard such as Methylene Chloride, 1910.1052, sets expectations for sampling and recordkeeping.

What we haven’t discussed is using “Objective data” to estimate employee exposures but the requirements can be found in 1910.1052(m) Recordkeeping (1) Objective data which states:

“(i) Where an employer seeks to demonstrate that initial monitoring is unnecessary through reasonable reliance on objective data showing that any materials in the workplace containing MC will not release MC at levels which exceed the action level or the STEL under foreseeable conditions of exposure, the employer shall establish and maintain an accurate record of the objective data relied upon in support of the exemption.

(ii) This record shall include at least the following information:

(A) The MC-containing material in question;

(B) The source of the objective data;

(C) The testing protocol, results of testing, and/or analysis of the material for the release of MC;

(D) A description of the operation exempted under paragraph (d)(2)(i) of this section and how the data support the exemption; and

(E) Other data relevant to the operations, materials, processing, or employee exposures covered by the exemption.

(iii) The employer shall maintain this record for the duration of the employer’s reliance upon such objective data.”

This can be relatively easy when an employer has two facilities with exactly the same or very similar work stations, floor plans, ventilation, and processes, etc.  Otherwise, you put your trust in the description of a workplace in some other company’s report that seems similar to yours but may have undescribed features that make the employee exposures different than on your site.  This is one thing when the data shows exposures are well below the exposure limit but when they are about ¾ of the limit your best bet is to conduct your own sampling which has its own set of recordkeeping rules.

1910.1052(m)(2) Exposure measurements

(i) The employer shall establish and keep an accurate record of all measurements taken to monitor employee exposure to MC as prescribed in paragraph (d) of this section.

(ii) Where the employer has 20 or more employees, this record shall include at least the following information:

  • The date of measurement for each sample taken;
  • The operation involving exposure to MC which is being monitored;
  • Sampling and analytical methods used and evidence of their accuracy;
  • Number, duration, and results of samples taken;
  • Type of personal protective equipment, such as respiratory protective devices, worn, if any; and
  • Name, job classification and exposure of all of the employees represented by monitoring, indicating which employees were actually monitored.

(iii) Where the employer has fewer than 20 employees, the record shall include at least the following information:

  • The date of measurement for each sample taken;
  • Number, duration, and results of samples taken; and
  • Name, job classification and exposure of all of the employees represented by monitoring, indicating which employees were actually monitored.

1910.1052(m)(2)(iv) The employer shall maintain this record for at least thirty (30) years, in accordance with 29 CFR 1910.1020.

Yeah, yeah, it seems like a lot of twiddly paperwork but what you are really doing is getting the best ‘bang for your sampling buck’.  You can identify conditions that are the same as the sampling day, meaning you don’t have to conduct further sampling.  You can identify changes in conditions that will result in lower exposures, so you don’t have to conduct sampling again.  Or, you can identify conditions that could increase employee exposures beyond limits and you must conduct sampling.  If this data shows employees are now overexposed those employees must wear respirators until engineering and work practice controls are proven to reduce exposures back below limits.

If you cannot identify such changes with your sampling data then any change in conditions could require resampling.  You also cannot use your sampling data as Objective data for other facilities.  I’ve been told some of my articles are too long, too much information.  I’ve been told no one wants to read more than 800 words.  Well, if you think this is long you should see my reports!

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