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How Often Do I Have to Monitor?

Our customer service team receives many calls from customers needing a little technical support.  Not surprisingly, some questions are more common than others.  The most common?

Since we have already addressed the first two questions, it is time to focus on the last question.  How often do you have to monitor?

But before I get into this– a disclaimer.  Most of what follows is my/our opinion after over 17 years in the industry and talking to our customers, many of whom are experienced and educated safety professionals (CIH’s).  So this is an experienced response written to nudge inexperienced customers in the right direction.  However this is not professional direction from an experienced and certified industrial hygienist that has investigated your facility. OK, back to the helpful nudge in the right direction. 

Many customers are looking for a straightforward answer.  Some call, annoyed at why we don’t include it in our instructions.  Something like, “You must monitor every employee quarterly.”  Obviously, we would love to offer this easy-to-follow rule to our customers, but it usually isn’t so easy.

Instead, OSHA directs us to perform representative monitoring and leaves it up to the employer to decide what that means. Why? Well, consider these two companies:

  • Company A has 100 people in their building working with methylene chloride every day. Sometimes, it’s hot and they open all their windows. Sometimes, it’s cold and the windows stay shut for months. Some employees are pouring methylene chloride. Some are in the same room, but never handle it. Some are working desk jobs in a room next to the room with methylene chloride. And finally,  there is a day shift, swing shift, and graveyard.
  • Company B is a dental office. Once in a while they use Cidex (glutaraldehyde) to clean their scopes. Approximately once a month, vented in a hood.

If you were the safety officer of Company A and understood that OSHA expects you to monitor enough so you can assure yourself you aren’t overexposing your employees, would you monitor:

  • Each person, every day?
  • Only the people handling the methylene chloride get monitored once a year, unless something changed in the facility?
  • Only the people handing the methylene chloride, once?  If there was no problem, then don’t do any more monitoring until there is a complaint?
  • Etc, etc.

If you were the safety officer of Company B, would it make sense to monitor everyone, every day? No way. Once a month? Probably not. Once a year? Maybe.

Safe to say, since Company A has employees exposed daily, their monitoring program is going to be more robust than Company B. If OSHA created a detailed rule it would be difficult to impossible to have a policy that was adequate for Company A and not be overly burdensome on Company B. So, there is no rule for how often you need to monitor the air.  Only that you have to perform enough monitoring so you have data that represents the environment to which all your employees are exposed.

When customers do call, we can’t tell them what to do.  If you are looking for someone to tell you what to do, we could forward the contact information of some consultants we know. But after being in this business over 35 years, here are a few thoughts:

  • If an employee complained to OSHA, you need to have enough data so you can make your case that the company did what it could to show their work environment is safe. If the only air monitoring you have performed was from 2005, do you believe you have enough data to make your case? Thus, create a monitoring program you would be happy to show OSHA.
  • You could monitor every employee every day, but that would cost a lot of money and are you really getting value out of each monitoring? Is there really any expectation that Monday, Tuesday, Wednesday, etc, are any different? If not, then everyday monitoring is excessive in most cases.
  • If you have 10 monitoring events and show the exposures are under regulatory limits, and then get one that is high for no reason you can think of, is it time to panic? Probably not. We suggest customers never make any huge policy decisions based on only one data point. Confirm results that are different from the norm. If the next couple of tests are low, then the high result is not representative of the work environment.

When it comes down to it, you, as the safety officer, have to build and manage a program that assures the working environment you are providing your employees is safe. If OSHA was ever to knock on your door, you need enough data to demonstrate that the company did everything it could do to assure a safe work environment.


For a list of my other Posts like this go to Steve’s Technical Corner List.  Have a question you’d like answered?  Contact Us