Industrial Hygiene in Construction

As you may know, sometimes tin knockers (aka sheetmetal workers)  use sheet lead, or lead soldering, to make flashing on roof vents. Here is a picture of what these commonly look like (if there is (?) a common one).

The lead iron is heated up. Lead solder, or sometimes lead/zinc solder is used. Muratic acid (or similar) is used to clean the stainless steel. The iron is used to heat up the solder and drip it on the stainless surface. Anyways, the process creates lead fumes. This is dangerous both from airborne inhalables to the contact surfaces surrounding the area.

The surfaces around these areas are usually very high in lead content. There is not a OSHA standard for lead wipe tests. However, in the past OSHA has used the HUD standards and cited employers under the general duty clause. If you are performing these tasks, please make sure you are doing everything you can to limit the airborne, dermal, and ingestion exposure.

• Follow OSHA Lead Standard (1926.62).
• Train your employees.
• Ventilation (downdraft is best). This is the best way to control the fumes.
• Post signs in the area “lead work and hazardous”.
• Perform air monitoring. I have found levels both above, and below, the exposure limits.
• Wear a respirator (1/2 face negative air with HEPA).
• Do not: eat, drink or smoke in this area.
• Good hygiene. Wash after doing these activities.
• Use a plastic sheeting on all surfaces. This makes it 100x easier to clean up.

in other words, don’t do what is in this picture below:

I had posted a few weeks ago about a recent sighting of silica exposures during concrete/asphalt cutting. Then, today, at a stoplight…there it is.

A worker was using a gas powered hot saw (cut off saw) with an abrasive blade to cut a concrete pipe. No respirator.

If you were me, what would you do? (Leave your answer in the comments section)

• call the company main office?
• stop and caution the employee?
• call OSHA?
• take a picture and post it for the world to see (check…ha)
• offer to buy a respirator
• perform air monitoring for them? (for free, of course.?)

This blog-post is directed to employees….the drywall framers, hangers, tapers, fireproofers & plasteres who sand and finish mud & drywall.

Question: What type of respirator do you wear when you sand?

…answer? Anything I can find.

This question misleading… and is similar to the one where the attorney asks in divorce court, “Do you beat your wife only when you’re drunk, or all the time?”

But, reiterate.  Do you ever NOT wear a respirator when sanding?  Answer: No. We always wear a respirator. It’s dusty.

So if I may ask a leading question (as a bad attorney): What type of respirator would you wear if you were worried about OVERexposure?

Answer: a tight fitting 1/2 face (or full face, for eye protection & fogging control) negative pressure respirator with HEPA cartridges.

I think I’ve made my point. Why would you choose a paper dust mask? The fit is mediocre, they are disposable, you cannot fit test them (very well). Who cares if it’s a N95 or P100. You can feel the dust escaping around your nose. Below are some “average” pictures of people sanding. What will you do?   more info here

There is much confusion over the requirements and best practices of employees using respirators voluntarily.

Let me first clarify. You must do air monitoring (or have other verifiable information) that employees are not REQUIRED to wear respirators (if they are overexposed to something, you must protect them). Also, they cannot voluntarily wear a respirators if there is a known hazard above the exposure limit (the employee cannot opt-out of wearing a respirator and be overexposed).

Some points about voluntary use:

• Assuming the above statement (s) is true, firstly, you do not have to allow them to wear respirators. I am sure this is arguable from a human resources/PR/legal stance. However, if you have documented no overexposure and have not provided a respirator, they should not need to wear one.
• Next, the employees need to be educated and you need to prove it. Having them sign Appendix D of the OSHA respiratory rule is a minimum. Training them would be better.
• What respirator are they wearing? A paper dust mask (N95, P100, or similar) is a respirator. If they are wearing anything other than this type of mask they need a medical evaluation (Appendix C of respiratory standard).
• If they are wearing a 1/2 face tight fitting negative pressure respirators (or more protective ones) the company needs to have a written respiratory program.
• Fit testing is not required to be performed
• Maintenance, inspection, storage, and training should always be done. Can you verify that the employee does this?

I personally do not recommend the paper dust masks (N95, or similar) for this simple reason. Why would you wear this type of respirator if you could have a 1/2 face, tight fitting one with the correct cartridge? The cost difference is negligible, the protection is better, and you can be assured of a better fit. If you’re going to do it, do it right.

Background: We arrived at the welding /fabrication shop where they were working on stainless steel. We were the first to arrive and found this next to the project.

I found 3 things that were blatant “no-no’s”. Want to guess? (see my answers below) You might find more.

1. respirator sitting out -not put away in box (actually sitting next to it!)
2. grinder without a guard
3. eating/drinking in the work area (gum, drinking cup)

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.

During mild steel welding I very rarely see respirators being worn. I believe this to be “standard practice” (the act of NOT wearing a respirator). However, is this a good idea?

The correct answer is:  It depends.

Explanation:

• I actually think during common mild steel welding, respirators should not usually be required. My experience in air monitoring has demonstrated that most “average” levels are well within occupational exposure levels (OELs).  While sampling under the hood (placing the filterpiece inside the welding hood), the flash hood protects from a lot of exposure. Most of the particulate that is seen-visually is iron.

Caveats:

• “average” welding changes everyday. What is average at one fabrication shop may be totally different from another. Each project may have different welding exposures. Welding inside a 36 inch tube is different than in an open field. You should roughly know what airborne levels you have at your site.
• If the welding contains metals other than what is in typical mild steel (and many times there are other stuff), the air levels can vary. Steel nowadays is so much recycled metal that there is a huge variability in the makeup of new product. Exotics (stainless steel, etc)  and known contaminants (leaded paint, coatings, oils, etc) should be treated very different.
• Long term exposures from metals might be a real health concern. There aren’t many metals in mild steel that you need to inhale.

Finally:

To wear respirators is a good decision. Conditions change and, in construction, this might be every hour. When the project needs to be completed quickly, most welders will not run to the store for a respirator. It is nice to be prepared.

My advice is to issue half-face tight fitting respirators with HEPA (high efficiency particulate air) filters. Train employees WHEN to use them and, if you have safety culture that permits it, trust them to use it when conditions warrant their use.

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.

Leaded sheetrock is what the name says, sheetrock with a lead layer. It is used in hospital x-ray rooms and other health office clinics for containing / controlling the emitted x-rays while the machines are in use.

Plastering / Drywall companies who install this type of drywall need to follow the OSHA Construction Rules for lead work. I have heard of airborne exposures being at the exposure limits (50 ug/m3) during the installation due to the cutting and breaking of the drywall. My own personal monitoring has been below the Action Limit (30 ug/m3), but I have consistently found levels above the detection limit. This information should be taken as a caution to others.

For starters the employer will need to provide:

• half face negative pressure tight fitting respirators with HEPA cartridges
• protective clothing (like Tyvek (R))
• containment (for the dust generated)
• training (in lead and respirators)
• hand washing / changing areas
• HEPA vacuums for clean up
• possibly air monitoring (by a qualified industrial hygienist)
• possibly blood lead testing

The sheetrock should be contained during transport. Installation should be performed in a contained area with employees in respirators who are trained and competent. Clean-up should be done with HEPA vacuums. Air monitoring should be performed to assure that employees were adequately protected during their activities.

Working with this type of material is no excuse to cut corners (no pun intended). Protect your employees, the hospital, the patients, and others.