Industrial Hygiene in Construction

Here’s my top 10 recommendations as it relates to Construction Industrial Hygiene:

I recently heard a very good summary of when (or alternatively when-you-DON’T) need to perform air monitoring when working with lead in construction.

Is there leaded-paint (lead based paint) in your project?

• Then you MUST comply with the OSHA lead in construction rules.

On what occasion do I NOT have to perform air monitoring?

• if you don’t have lead (see the first question)
• if you want to provide the minimum required protection for all of your exposed employees (respirators, blood lead monitoring, etc. etc.)
• if you have historical air monitoring data (from another project) that supports the methods you are using

Otherwise (in summary):

• Take a bulk sample of the paint
• Set up all engineering & administrative controls for controlling dust
• Train your employees
• Perform air monitoring during the FIRST day of actual work
• Continue with all controls through the project
• Notify everyone onsite of results
• Require that all subcontractor do the same process

OSHA states that:

• Medical exam – must be completed prior to wearing a respirator. The individual must be examined again if there are significant changes to their medical/respiratory system.
• Fit Testing– this must be performed yearly (either qualitative or quantitative fit test, depending on the respirator) and be performed for each type of respirator worn (not for each filter used)
• Fit Checks- these are performed every time an individual puts on a respirator. Cover the inlets and breathe in (mask should collapse). Cover the exhale valve and breathe out (mask should expand)

Individual cards for employees are not required. Sometimes, when filing the medical exam, the physician/medical reviewer, will not require the individual to come into the office. As a best practice, I would have every employee fill out the paperwork and see someone in the medical office. Employees have every reason to want to pass this “exam” and they may leave out things on the written exam that are easily discovered (or may be obvious) when someone sees them in person.

In construction there may be a time when employees need to weld on galvanized metal. This poses a unique problem since the zinc oxide fume can cause metal fume fever.  Should employees wear a respirator? Should mechanical ventilation be used? Should they drink milk? before? during and after welding? 

As with my answers to all welding types:  it depends.

However, I will make some generalizations. I have not seen a lot, or high airborne exposures (to zinc oxide) during galvanized steel welding. But, I typically recommend that welders are prepared and ready to wear a respirator if the need occurs. Welding is so variable, it is hard to make generalizations that cover all aspects.

Some questions that I ask before issuing respirators include:

• Does the welder have experience and training with this type of welding?
• How long will the welding occur?
• Is it spot welding? or for a duration of time?
• Is there mechanical ventilation in place, and can it be used for the entire project?
• Is there any portion of the welding that will be in a confined area with limited ventilation?
• Are there any coatings on the metal? Lubricants?

Once a respirator is decided to be issued, I only recommend a 1/2 face tight fitting respirator with HEPA filters. I know that N95 and other types of filtering dust masks do provide protection, but they, in my opinion, are not adequate if you really need them.

And, as far as drinking milk. If you feel sick after welding- drink it. It won’t hurt.

How much information should be contained in your written safety programs? There isn’t a right answer, but here are my suggestions and thoughts.

Have two “levels” of programs.

Corporate Safety Programs –

• This type should contain the general overview of the safety at the company. It should speak to the concern that the company has to the safety of the employees.  ie. “we don’t want you to get hurt, so…”
• No details. For example,  an Asbestos Policy statement – “As a company we anticipate that we may encounter asbestos onsite. We train our employees in identifying suspected asbestos containing material (ACM) and subcontract any work where we may disturb potential ACM. “
• Employees should be trained from the Corporate Safety Policies (initially, annually, or periodically thereafter).
• Establishing these programs should take a lot of thought, consideration, and buy-in from management and leadership.
• Do NOT make a policy that you do not plan on keeping. If you are going to occasionally do something which is a direct contradiction to your policy – don’t make it a policy. I know, simple in theory, but…

Site Specific Programs

• These types of programs should contain the details. Who, what, when, where, how.
• Only include the policies that you have at the jobsite- otherwise don’t have this policy on file in the trailer.
• Cut and paste the policies you need for this specific job – from your corporate program list.
• Another example, from the asbestos policy, “on XXX project we have identified asbestos in the blue and green 9×9″ floor tiles to contain 5%asbestos. ABC Abatement Company will abate and remove any asbestos found. If additional materials of this size, shape, color are found, please notify the superintendent immediately”.
• Perform tool-box talks from your site specific programs. These programs should have enough detail that your Project Engineer could read it to the employees and have enough information.

One of my pet-peeves is reporting industrial hygiene results with absolutely no explanation of what happened (or the conditions) on the day of the survey. The results will never be reproducible, verifiable, or really ever used again. If you are going to perform the exposure assessment, tell us what happened. We all know that an “average day” is rarely ever the average.

Sometimes you are not able to choose the time when you are able to perform air sampling or monitoring. But, that is a very important part of the overall picture of the exposure. When sampling I very frequently hear, “You should have been here yesterday”, or “Today is really slow”, or “Can you come back next week when we are doing XXX activity?”.

Those phrases and employee interviews are almost as critical as the air sampling results. They tell you what you DIDN’T see, or capture in your exposure monitoring.

At a minimum you should tell a story about:

• what engineering controls are in place
• what administrative controls are used
• what are the employees doing
• how often does this occur
• is this a worst-case scenario, or just average day
• what happens during set up and clean up
• what products are they using (MSDS)
• what PPE are they using

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.

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?