Industrial Hygiene in Construction

Sometimes it is extremely hard to protect the hands of people in construction. A typical construction worker may need leather gloves all day…until the end of the shift when he uses the solvent to clean his tool. Previous cuts, scrapes and scabs make it easy for chemicals to enter. And, depending on the chemical, it may absorb through the skin, or at least, dry it out.

Below is a employee’s hand who had been working with acetone for years. He badly wanted his hands to feel better.

Here is a link to an excellent article by Donald Groce at EHS Today.

The question I commonly hear is:

Do I need to wear a respirator while cutting concrete wet? What, if so, what type?

To simple answer is, yes.

If wet concrete cutting is done correctly, you should not need a respirator. However, what happens is that in the field, many variables occur. ((Engineering Controls)) Sometimes the water will be directed at the top of the blade (for cooling, not for dust control). The water must be directed at the cutting site on the blade in order to control dust.

Another variable is ((Administrative Controls)) clean up. Do the workers clean up the wet slurry? Or, do they wait till it’s dry and then use a leaf blower?  Do they vacuum the slurry? What happens when the job is done and the vacuum is in the shop? Does the employee wet it down, or blow it off?

Also, what happens when your worker is cutting wet and the water stops? Does he continue? What about if he get to a curb? Do they get the Stihl hot saw and cut wet? What if they don’t have water for that saw?

So, technically, if done correctly, a respirator should not be needed. However, if you don’t have the protocols, air monitoring data, and management controls in place to do it correctly, get a respirator.

Which respirator, you ask? Minimum would be a tight fitting negative pressure half face with HEPA filters. If they are knowingly performing concrete cutting dry – then it needs to be a full face respirator.

To simplify OSHA’s rules for lead in construction this is how I explain it:

Do you have lead (lead in paint usually) on the construction project? …Then you must comply with the entire rules.

How do you start? You start by listing the tasks where you will disturb the lead. For example, demolition, hand scraping, torch cutting.

After you’ve identified the tasks, then you can look at the OSHA rules and determine the minimum personal protective equipment (PPE) that will be necessary for your employees to wear while they’re performing each individual task.

Next, train your empoyee’s in lead awareness, which is the dangers, prevention and hazards of lead poisoning.

There is one other important aspect. Measuring your airborne levels of lead. This is done by air monitoring with a battery powered pump (and is typically one role of an industrial hygienist). Airborne lead results will indicate if you are generating a lot of lead into the air, or not. If you’re not, you can sometimes downgrade (bad word) the level of respiratory protection for your employees.

• Caveat: this is not a complete summary of the rules. Please know and understand your local and federal rules entirely! This also does not cover the EPA’s Lead Rules which have specific items that you must do.

I have done a bunch of respirable silica dust air monitoring during drywall sanding activities. I have found varying results from the data (meaning overexposures & within the exposure limits). I have found silica in the drywall mud (or possibly the drywall itself).  I have also found that most drywall sanders wear a paper dust mask. In recent years I have not found any airborne silica in my samples. However! I have found airborne (total) dust levels higher than five times the exposure limits during sanding. What does this mean?

Well, the issue is that most drywall sanders use paper dust masks, or equivalent N95 or P100. Like this.

NIOSH has rated these masks for a protection factor of 5. Meaning that you are “allowed” to be exposed up to 5 times the exposure limit. IMO there are many things wrong with these masks. For starters, their fit on your face is really a guess. There are no “tried-and-true” methods for assuring these masks fit.*  Second, if you admit that you need to wear a respirator (meaning: you need to protect yourself) why would you choose an inferior product? I could go on…

Therefore, or finally, we come to my recommendations:

• if you’re drywall sanding:  wear a 1/2 face tight fitting respirator with HEPA cartridges. It will protect you (given a proper fit) and based on my findings, you can rest assured you won’t be overexposed.

Besides who wants to look like this at the end of the day?

*Quantitative fit testing is a reliable fit test method, but for these types of masks, I find it to be totally useless in the real-world

Many bridges and elevated highways have leaded paint. Lead and cadmium was (and sometimes still) added to paint for durability. Nowadays other heavy metals are used for durability. This particular bridge was near the coast and had already been repainted sometime in the past. Repainting requires the removal of the existing paint by sandblasting.  Since the bridge was previously  repainted with a non-leaded paint, in theory, there should not be any airborne levels of lead, or cadmium. However, I always find airborne levels of lead. Why?

The possibilities are:

• not all of the leaded paint was removed
• recycled blasting agent has trace amounts of lead
• and possibly there are still levels of lead in the new paint that is supposedly “non-lead”

I always ask the laboratory to analyze my air sample for lead, and cadmium. Lead is usually the main contaminant, but occasionally I find cadmium. I will sometimes also have the lab check for zinc and chromium.  The sandblasters wear hooded powered air supply respirators, coveralls, and ear protection while blasting. Some other time I’ll talk about the noise from that activity (it’s LOUD!) and the fall protection issues they face.

Lead is a hazard in two forms: 1. airborne and 2. ingestion- from the transfer of contaminated hands/clothing to being eaten. Hygiene on a lead project is essential to preventing these exposures. A good safety practice, by which to verify that lead is not being transferred is to obtain wipe samples at random (or not-so-random) locations. Lunchrooms, shower/change areas, and pickup trucks are some of my favorite “random” locations.

The views around the area weren’t bad either…

To summarize,  there is no real quick-fix to this type of industrial hygiene assessment. Depending on what type of spray finishing you are performing- will depend on how to proceed. Here are some things to look during your assessments of these areas:

• air flow across the face of the spray area should be at least 100 feet per minute
• review the MSDS for the products you spray, and the solvents, thinners, and A+B parts-everything.
• check the filters – are there scheduled changes? a manometer in place and used?
• no flammables should be inside the booth area
• watch the flow of work- usually there can be improvements- as well as lessons to learn
• is the employees’ skin protected during spraying? (obviously not in the picture-right)
• where does the waste (left over) spray product go?
• ask employees about concerns and health issues

Typically respirators are worn in the spray finish areas. This list is not complete, but for starter, check:

• what type of respirators are being worn? Are they protective enough?
• what type of cartridges are used? Are they changed regularly?
• are there scheduled change out times for their cartridges? where is that posted?
• where are their respirators stored?

I know, the title is wrong.  It should read:  “How to prevent hearing loss“.

Here’s the problem (IMO).  I think most people know how to prevent hearing loss- and in America we can all afford to buy ear plugs. I have also heard of hearing loss claims that are unfounded and totally unrelated to their current work activity.  Even just a one time loud event can cause permanent hearing loss.

Construction companies hand out ear plugs like candy and say, “wear them when it’s loud”. Then, these same construction workers go home buck-up a cord of wood, ride their motorcycle, shoot their gun, and then after dinner go to a rock concert.

So, to avoid a claim, here is my advice:

1. Measure the noise (by dosimetry) at your job site- and do it annually.
2. Start a “hearing conservation program” or, in the simplest words, have your employees’ hearing checked annually.
3. Educate (train) your employees in hearing conservation
4. Give them choices in hearing protection (different brands of plugs, muffs, etc.).
5. Manage their hearing- (see below)

If you notice a loss in their hearing- do something! To manage possible hearing loss, I suggest these additional steps:

1. Retest their hearing. On a Monday, before work.  (To avoid a possible temporary threshold shift)
2. Have another company test their hearing. (sometimes the equipment is out of calibration)
3. Remind your manager to enforce the employee’s use of ear plugs on the job site.
4. Offer to give them ear plugs to take home.
5. Have an Industrial Hygienist (IH) perform noise monitoring at the job site for the full shift (dosimetry).
6. Retest their hearing again a month or two later.
7. Have an audiologist review their audiogram & your noise sampling data and ask for an opinion.

A suggestion brought to one of my postings was, “how do you control the exposures?”. The answer, …in my best legalese was, “it depends”.

There are many ways to control the exposures.  However, as an general rule there is a method of approach that is best. OSHA describes it in some of their rule-language (such as lead 1926.62, and others).  So the first step in controlling an exposure is:

1. Engineering controls

What this means is: Can we remove the hazard from the employee. The best method is elimination. Using a different product that is less harmful can sometimes be discussed. Next, can we control the substance so that it is not harmful- like using a local exhaust ventilation? Can we use water to control airborne releases? Engineering controls should always be considered first. I suggest that when you have an exposure situation, have your safety committee brain-storm these types of controls and document them. OSHA has issued citations for employers who choose NOT to consider this control.

2. Administrative controls

These types of controls are a bit harder to describe. Suppose your worker must go into a high noise area multiple times during their shift – the answer might be limiting their time in this area. And possibly allowing other employees to “share” this exposure during their shift.  Another example would be having a protocol that minimizes airborne exposure by a method of work that is enforced by management.

3. Personal Protective Equipment (PPE)

This should be used as a last-resort. Most times it’s not. The reason it is NOT used is usually because of convenience.  However, there are many ways this control can fail including, improper use, breakthrough, permeation, penetration, degradation, and failure.