Industrial Hygiene in Construction

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
   • fill out a questionaiire (just like Appendix C of OSHA)
   • they might have you perform a lung function test (spirometry)
   • you will get a yes/no answer (probably 99% are approved)
   • you might try an online medical evaluation
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.

People who work in industrial hygiene try NOT to admit fault. There are reasons;  legal implications, credibility, and of course, pride. Since this blog is about being transparent, I will confess I made a huge mistake. My mistake wasn’t disastrous, but it could have been.

Background:

Employees were using a hudson sprayer (pump style) to apply a liquid waterproofing material. Air monitoring was performed and found to be 50% of the OELs. However, given the environmental conditions, and different areas they would need to access, I recommended they wear 1/2 face respirators. The hazard was isopropyl alcohol and a 1/2 face respirator with organic vapor cartridges was sufficient, with goggles & protective clothing.

However. It wasn’t isopropyl alcohol….it was methyl alcohol (methanol). And, there is a HUGE difference. Organic vapor cartridges (filters) provide NO protection to methanol. I should have recommended supplied air respirators.

I feel terrible, and I apologized.

“Success does not consist in never making mistakes but in never making the same one a second time” – George Bernard Shaw

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

I’ve mentioned this before.

If you’re using these tools in construction please be careful.

Quick summary:

• the powder contains lead (Pb)
• you can be exposed to lead when it is airborne, AND if it gets on your hands & you eat it.
• lead is not healthy for kids
• Wash!

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.

If you operate a ready-mix plant and have concrete trucks, you are aware of this process. Once a year (hopefully, only once) a person must climb into the drum of the ready-mix truck and chip off excess concrete. What happen during regular use, is that some concrete hardens, which usually sets-up over and around the blades. Access into the drum is by either the 3×4 hole in the side, or down the chute.

Yes, it is a confined space (def’n: 1. large enough to enter, 2. not designed for occupancy, and 3. limited entry/egress).

Here are a list of the possible hazards:

• silica dust (from chipping concrete)
• noise exposure
• hazardous atmosphere (curing concrete uses up oxygen, which we DO need BTW)
• slipping hazard (drum is round inside)
• heat stress (if you’re trying to do this activity in the summer)
• eye hazard (chipping)
• electrical hazard (if you’re using water & have an electric hammer)
• lock out / tag out (if the truck drives away, or if the barrel starts turning)

There are many resources available (see below). Some things to keep in mind; ventilation (fans, etc) to control the airborne silica dust are usually not effective (too much dust versus exhaust). Water controls are best, but you must limit the amount of water and the direction of the sprayer. I suggest looking at what others have done.

Keep in mind, if you perform this activity you will need (as a company):

• respiratory program (medical, fit test, written plan)
• confined space program (multi gas meter, written program, attendant?)
• lock out /tag out policy or procedures
• training (for each of the above, and for this specific activity)

At this point I know what my contractor-friends are thinking…I will subcontract this out!   ha. If you do, please make sure your sub is doing it right.

Resources:

Georgia Tech – good presentation & guidance

Georgia Tech/OSHA – Safe Work Practices (in Spanish too!)

Teamsters H&S hazards & controls

Illinois DCEO – Consultation on ready mix cleaning

There are two types of fit testing, 1. quantitative and, 2. qualitative. For quantitative fit testing you’ll need a machine (ex. Portacount),  a respirator that will protect more than 50x the limits (>full face).  I will not cover this type of fit testing in this post, but it is very similar.

For qualitative fit testing you will need:

A medical clearance (not needed if you are wearing a paper dust mask) for each employee wearing a respirator.

Respirator w/P-100 filters (1/2 face respirator or more protective), aka HEPA filters, purple in color.

fit test kit -your choices are: saccharine, irritant smoke, Bitrex, or isoamyl acetate-bananas. Buy it online, or at your local safety supplier. Look at their instructions.

My preference is to use irritant smoke. The reasons are;

1.  if they cough, it means they smelled it.
2. it doesn’t require a containment to be built to perform the fit testing.

The employee must be clean shaven around where the mask touches the face.  I allow “short” goaties where the facial hair does not touch the mask. The fit test procedures are easy to follow and found inside the kit. There are 8-steps, do each one for about 1 minute each.

As you fill out each individual’s form, make sure you include:

• if the employee is clean shaven
• what type of respirator is being worn (size, brand, model)
• what type of filters are being worn
• what type of fit test kit you used

While you have the employee captive, you might as well give them some training. Here are some questions and/or points to note.

• did you train them on positive & negative fit checks?
• why are they wearing a respirator?
• what are the limitations of their respirator?
• how will they store the respirator?
• how will they sanitize it?
• will they share their respirator?

Finally, sign and date the form. It expires one year from this date. Simple? yes.  Easy to forget something? yes.

Living in the NW, stucco is not as prevalent, compared to other areas of the US, as a building material. I finally got the opportunity to perform air monitoring for silica during stucco crack repair. From what the contractor explained, only the top layer of stucco (1/8 inch) is removed. He claimed the top layer is mostly an acrylic. The employee was wearing a 1/2 face tight fitting respirator with P100 (HEPA) cartridges. In addition, engineering controls were used.  The contractor had a grinder with a shroud and vacuum to remove the dust. This would not be considered a worse-case sampling scenario. From conversations with the plasterer-employees onsite, grinding is usually “VERY dusty”.

Sampling performed only for the duration of the grinding (3 hours). Conclusion?: We did not find any detectable levels of silica or respirable dust.

Please don’t use this sampling as the only information on how to proceed for your project. However, here are my observations:

• If acrylic material is the top 1/4 inch, you may not impact silica (or have any airborne).
• Airborne dust was very well controlled by grinder with shroud & vacuum (see pic below).
• Assume you will have dust until you can observe (or prove) otherwise. Wear a respirator.
• Perception is huge. If there is a big dust cloud coming from your grinder—even if there’s no silica… the observers don’t know the difference, and, well,…you know the story.

 

‘Tis the season for silica (here, and here too).

I had four observations about this picture,

1. paper dust masks are totally inadequate for this task, and
2. why isn’t there any engineering controls (water?, vacuum?), and
3. why is the observer standing in the dust plume?, and
4. what does the employees do with their clothes after work?

Please be safe out there.