Industrial Hygiene in Construction

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:

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

Background: A new client recently had an OSHA health inspection (industrial hygiene). He received citations stemming from overexposures(they found levels above the PELs) to airborne particulates.

The company wondered what to do next. Here were my suggestions:

• Fix the problem. You will need to comply and assure that your employees aren’t overexposed. Even if the inspection made you upset, use your energy to make the situation right. Focus your energy on removing the hazard, not complaining about how you were treated.
  • Engineer the problem out. Remove the hazard. If not,
  • Change your policies so no one is further overexposed. If you can’t fix it by the this, or the above method, then,
  • Provide personal protective equipment to affected employees.
• Request the full inspection package. – this will include the officer’s field notes, interview questions, observations and sampling methodology.
  • look through these documents carefully
  • keep them for your records
•  Informally appeal the citations.
  • at the appeal show them you have complied/changed
  • ask for a reduction in fines (it never hurts to ask)
  • ask to group the citations together – instead of citation 1 item 1a, 1b, item 2, etc. ask to narrow it down to just one
  • bring any additional information which supports your side and/or the changes you’ve made (including training docs, programs, policies, etc.)
• Resample the areas.
  • make significant changes to these areas. Then,
  • hire an industrial hygienist to perform additional sampling in these areas
  • ask them to document the changes you have made to reduce the exposures
  • review this with your safety committee & those affected

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.

As you might be aware, there is a loudness of noise which your ears cannot be protected against. Your body’s system of preventing the sound waves from entering your ear are just too much for it to handle. As the noise (sound pressure) hits your inner ear the bones convert the physical energy (noise) into a chemical & neurological process so you are able to hear. Ear plugs and ear muffs are not sufficient enough to protect against the amount of noise exposure.

However! Sometime in the future we might have a pill to prevent this type of hearing loss.

Researchers have found that the chemicals, D-methionine, ebselen & N-acetylcysteine, battle chemical stress on your ears.  We are still a long way from being able to take a pill to avoid hearing loss. They must go through more testing and the FDA approvals.

But, isn’t that cool!?

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

The first question is, “why is this useful?“. Well, generally speaking, it is helpful to know if you are getting bare-minimum airflow, or if you are creating a wind tunnel on your project. Since many construction projects are not able to mobilize until the last minute, it is useful to make some rough guesstimates and calculate the airflow in the room. One squirrel-cage fan isn’t going to ventilate a warehouse, and 5 of them in a manhole will make welding impossible.  so…moving on.

Air changes per hour (ACH) is a function of the room size and the airflow into/out of the room. It is simply the number of times the volume of air is changed out over a one hour time period. One reason this calculation is so attractive to use is because there are recommended exchange rates for different environments. Some of them can be seen in the picture, the rest can be found here.

To calculate you must know:

• A = Volume of room in cubic feet (ft3)
• Q = Air flow of your fan (s) in cubic feet per minute (CFM)

Rather than reinvent the wheel Wiki has a good summary.

Caveat/Disclaimers. There are quite a few…so be careful.

• Mixing. The air never really mixes when you are exchanging air in this manner. It is dilution ventilation. So,
• Never use this method for any hazardous source, and
• Never use this for any carcinogens (asbestos, benzene, etc).
• Airflow into & out of the space is required, and is never ideal. Make sure there is space for the air to actually exchange.
• Make sure your fans work properly and do provide the manufacturers output.

While doing airborne silica sampling I noticed this industrious employee using not one, but TWO hands free mobile devices. This guy can multitask!

I think flip phones might be making a comeback.

After performing an industrial hygiene survey (air monitoring), have you considered when you should resample? Here are some considerations that might help you in determining when.

• Are there specific rules that state when you must resample? For example, the construction lead standard (1926.62) states that you must resample yearly (or actually, that you can only use relevant results for one year).
• Has the process changedsince the last time you sampled? This one is hard to determine. Lot of things can change air monitoring results, here’s a “starter list” of things that can change a process.
  • Different employee?
  • Time of year? Summer versus winter? (closed up/open and humidity)
  • Is a new tool in place?
  • Has the ventilation changed?
  • Have new controls been put in place? (administrative, systems operations)
• Has the product changed? Check the safety data sheet (aka MSDS).
• Are more (or less) employees exposed to this hazard? This might change some assumptions you have made about your risk.?

If you have air sampling performed, make sure you have a written report of your findings. Laboratory results without an explanation of how they sampled, where, # of employees, process description, PPE used, safety data sheets, etc….is worthless. You may remember is well enough, but OSHA will have a hard time believing that it is a similar exposure the next time you do the “exact same thing”.

Having this report and sharing it with the employees will fulfill (part of) the hazard communication standard requirement to employees.

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.