Biological Monitoring


NIOSHNIOSH has just recommended a new exposure limit (REL) for hexavalent chromium. The new limit is 0.2 ug/m3 as an 8-hour TWA. If you remember, the OSHA PEL is 2.5 ug/m3 (8-hour TWA). SO, if you’re good at math, you can see this is A LOT lower.

The reasoning for this level is they have found a lung cancer risk (get this) EVEN AT 0.2 ug/m3. They recommend bringing airborne levels below this limit for lung exposures.

As I’ve described before, exposures are not limited to just inhalation. Dermal contact is a big concern.

If you have any hexavalent chromium at your facility, or stainless steel (welding, welding2hardfacing, etc.) you need to do more than just air sampling. You need a comprehensive program including wipe samples, medical monitoring, etc. This may not be a specific OSHA rule for your facility.  However, these exposures are something you must manage.

 

Before you can wear a respirator here’s what has to happen:

If you’re an employer and your employees wear a respirator, they are required to have a medical approval (Appendix C of OSHA respiratory standard). more details here.

The employee fills out the confidential questionnaire and then submits it to the medical provider of the employer’s choice. 95% (I made that # up) of the time, based upon the questionnaire ONLY, they give an approval to wear a respirator.

Occasionally, some employees are requested to come into the medical office to have a spirometry test performed, which tests for lung function. (a video of how it is done, cool accent included) This tests provides more information for the physician/nurse to determine if wearing a respirator will be too difficult for an employee to wear.

The cost for either test is usually pretty close to the same price… spirometry test, or not.

Here’s my suggestion:  Have every employee perform a spirometry test before wearing a respirator. This helps to guarantee they are capable of wearing a respirator. Maybe they forgot to list a risk factor, maybe they have a hidden serious lung problem, or, maybe they lied on the questionnaire so they can wear a respirator and keep their job.?

It is also beneficial for pre-employment screening, claims defense, and for a baseline in health. The specific results are usually NOT view-able by the employer, but they can be subpoenaed.

 

Looking back at my lead in construction posts, I realized I did an inadequate job of summarizing why construction activities are dangerous when working with lead.

If you work in construction, here’s are the quick points as to why you should be concerned about lead.

  • There has been A LOT of lead added to paint over the years. (it can vary 0.01% to upwards of 20%, and there’s no way to tell by looking)
  • The activities we do in construction disturb this paint (some worse than others)
  • You can be exposed to paint by inhaling it (if it is airborne), and if you happen to get it on your hands and you eat it (by transfer).
  • The real concern is kids. (your kids, the kids who might be there after you’re gone, AND, the kids unborn (lead exposure can go from mom to baby)

The solution is simple (and, of course, more complicated as you dig in):

  • test the paint to see if there’s lead in it
  • if you disturb it, follow the rules (OSHA, EPA, HUD, City, etc.)
  • train your employees (and measure the lead in their blood)
  • prevent the dust from going everywhere (containment)
  • measure the air to see if you are really screwing it up, or doing a good job.
  • finally clean up. (the area, you, your hands, the perimeter) and dispose properly

There are some items you need to do BEFORE you wear a respirator. If you are using it on a voluntary basis, go here.

  1. obtain medical approvalfor employees to wear a respirator
  2. have a fit test performed
    • qualitative fit test unless you wear a full face mask, or a type better than this
    • my favorite choice is irritant smoke, but it could also be saccharine, isoamyl acetate (banana), or Bitrex (R).
  3. get trained. Learn how to:
    • clean it
    • store it
    • know what your respirator can’t protect you from
    • choose the right cartridges
    • know when you have break through
    • fit check (different than a fit test -BTW)

Wondering how often you must update the above steps? Go here. There are more steps to having a respiratory program, but you must do these things before you start.

You must follow both. (I’ve mentioned this before)

OSHA’s rules are very detailed and apply to any amount of lead in paint (even less than 0.5%) if you are disturbing it. The only time OSHA rules do not apply is:

  • if you are working as a sole-proprietor (no employees), or
  • if you are in some other country.

EPA’s rules are just a start. They apply to any residential facility where there are kids under the age of 6. OSHA’s rules are much more comprehensive and protective. (in some instances, overkill)

To EPA’s credit, they have done a great job of marketing and letting contractors know they insist on compliance. OSHA, on the other hand, only inspects 2% of businesses/year and does virtually no marketing. The chances of OSHA showing up on any given jobsite, is nearly 0%.

OSHA’s rules are very complete and comprehensive. You WILL need air monitoring, blood monitoring, PPE, change areas, water/sanitation, and training. The worst thing you can do is NOT follow the OSHA rules, find overexposures, and then try to “make up” for it. From my experience this scenario is a bad place to be, and happens all the time.

The answer is Yes.

If you are working with lead (in any amount) and you are performing any of the “trigger tasks” in construction = you must follow OSHA rules. Trigger tasks are demolition, removal, encapsulation, new construction, installation, cleanup, abrasive blasting, welding, cutting, torch burning, transporting, storing, heat gun work, sanding, scraping, spray painting, burning, welding, etc. What about the EPA rules (RRP)? Look here.

The only exceptions to not measuring employees blood lead are:

  1. On the first day of work activity, you perform air sampling (for the full shift) and can prove the airborne levels are below the Action Limits (<30 ug/m3)…or,
  2. OR…If you have relevant historical data and can prove your airborne levels during the same tasks are below the Action Limit (within the last 12 months). Relevant historical data must be REALLY relevant. Like, same work activity, same amount of lead in the paint, same general size/location, etc, etc.
These are the only exceptions.
If you choose to NOT perform blood lead monitoring the downsides are:
  • employees might already have dangerous levels of lead in their system, and you expose them to more
  • measuring blood lead levels after the exposure may indicate higher baseline blood lead levels -and you might have to pay for exposure which wasn’t your fault
  • if overexposed, and they have high blood levels – you might have to also check their family’s blood lead levels

More information on blood lead testing from my earlier post.

When clients ask me to assist in choosing a product, I try to recommend a product with the least dangerous chemicals in it. I understand this isn’t always possible. However, I try to emphasize the worst case health scenarios and leave it up to the company to decide how to proceed. There are reasons to use a hazardous (to your health) product.

However, here are some considerations when choosing a hazardous product:

  • more hazard vs less cost
  • more hazard vs less time actually using product
  • more hazard vs cost of PPE
  • more hazard vs what the spec says
  • more hazard vs different hazard
  • more hazard vs terrible health effect/potential
  • more hazard vs perception by others on the project (by the GC/public/subcontractors, media, neighbors)

Another issue with chemicals is the names and nomenclature. There are so many different names, common names, chemical names, and sub names of products – it gets confusing.

One solution called, ChemHat.org, offers a unique way of considering other chemicals. Plug in the CAS# (Chemical Abstract Number) or the name, and it gives you some ideas.

Another alternative in choosing the best product is to ask.

  • Ask your industrial hygienist if this product is safe and/or are there concerns?
  • Ask the GC if this is the only product that can be used
  • Ask the architect if there are alternatives that are equally effective
  • Ask the manufacturer if they have comparable products without the XXX hazard

You already knew it. There is a lot to do in industrial hygiene. At times this occupation feels like a safety middleman trying to keep people out of trouble. Occasionally I’m rewarded with really helping someone. In the United States, there is still a lot of occupational hygiene issues and concerns. Overseas, particularly in developing countries, there is even more.

It is hard to obtain accurate exposure data, or illness rates, from these underdeveloped countries. (How does a village of 1,000 people in Kenya report that they’ve had lead exposure to battery recycling?) How these exposures are brought to light is by either a massive death (# of people, quickly) or, someone with a camera able to actually photograph the pollution. As we know, what it looks like doesn’t necessarily correlate with hazardous levels of exposure. But, in some cases, it’s pretty obvious.

I ran across this photo story on pollution (The Guardian, UK). They estimate 125 million people are exposed to industrial pollutants (generic term, I know). This makes occupational related exposures a health risk as big as TB and Malaria! The article is based upon a report from the Blacksmith Institute which included this map of the worst pollution with associated disease.

How does this apply to construction? The worst offenders are lead (Pb) (and other metals), and asbestos.

What can you do? Here’s their recommendation, from the report (p50):

Developing countries need the support of the international community
to design and implement clean up efforts, improve pollution control technologies, and provide educational
trainings to industry workers and the surrounding community

Another NPR article about lead poisoning can be found here.

When taking blood lead levels, the occupational health clinic will typically measure both the lead in the blood, and the zinc protoporphyrin (ZPP). The reason for this is the blood lead level measures just that, only the lead in the blood – which can come from previous exposures and whatever amount has been stored in your bones (soft tissues). It really only gives one piece of information. An early indicator of  lead exposure is the ZPP level.

The ZPP level indicates lead absorption. If your ZPP levels are elevated, this may mean that lead is being absorbed into your body (affecting the heme synthesis pathway). However, an elevated ZPP can be caused by other things, including iron deficiency anemia, etc.

If you have elevated ZPPs, you need to find out what is causing it. If you’re working with lead, you may have overexposure. If this is the case, your blood lead levels will most likely elevate in 2-6 weeks.

Ask your occupational health clinic for ranges of acceptable blood lead levels and ZPP levels.

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