Industrial Hygiene in Construction

If you haven’t heard, Federal OSHA is proposing to reduce the airborne silica permissible exposure limit (PEL) to 50 µg/m³. It is difficult to say how much lower this new rule will be, since the current standard relies on a calculated formula to obtain the exposure limit. However, to make this easier, let’s just say it’s a 50% reduction in the PEL. This limit is the same at the NIOSH Recommended Limit and above the ACGIH Threshold Value of 25 µg/m³. Before I offer my opinion, you can state yours to OSHA here, and I’d recommend you do.

Benefits:

• Increase awareness by everyone (any news is good news for silica awareness)
• Further protect employees from overexposures
• Update the health standards. The original rule was from the 1970s.
• New products for the industry will be created to control silica, like this.
• Pretask planning (JSA, JHA) will become more common
• Consultant hygienists will get more $ to: train, air monitor, etc.
• Alternatives to sampling. This is written in the proposed rule.
  • Rather than air sampling, you can choose to “over protect” and assure employees have adequate PPE
  • This is great for short duration tasks where exposure monitoring is prohibitive (see Table 1. below from OSHA’s Fact Sheet)

Weakness:

• Employers will spend additional money:
  • on controls for silica
  • on labor during the activities
  • on consultants to verify you’re below the PEL
• OSHA will cite you easier
  • (my guess) is compliance officers will cite you for failure to implement controls, rather than measuring the airborne dust and finding overexposure
  • driveby citations. Look at some of my “caught on camera” overexposures. It is easy to see why this will be easy for OSHA to cite.
• More confusion
  • remember how you felt when you started working with leaded paint? Picture that again.
  • smaller contractors might be confused with the changes
• I’ve heard: the airborne levels trying to be achieved are so low, they are at the laboratory detection limits. (this is a bit beyond me, honestly, but it has to do with chemistry & analytical methods)

Overall, I think lowering the limit will reduce employee overexposures to silica. The increase in awareness across the US will bring more attention to the danger. Contractor employers who are doing absolutely nothing to control silica will get caught, punished, and hopefully change. For good-contractors out there, this will make it easier to explain to your subcontractors who are a little behind. I can see many contractors using Table 1 as a guide to easily protect employees on short tasks with high silica exposures.

Your thoughts? I’d love to hear them. Here is a NY Times Article perspective.

Yea, I know. Strange one, huh? In my time consulting, this is actually the second time I’ve come across this.

It is more commonly know as: Mace (R) or tear gas (not pepper spray though, that is Oleoresin Capsicum). Hopefully you haven’t actually experienced it’s exposure. It is worse (so I’m told) than pepper spray. More differences compared here.  All can be quantitatively measured by your favorite occupational hygienist.

Exposure in construction can come from incidental releases (incident response) or during clean up/ demolition of structures where this was used (think: police entry into a structure).

The OSHA exposure limit is 0.3 mg/m3. (NIOSH REL is the same, ACGIH TLV 0.35 mg/m3). They are all very low, actually.  Exposure can occur by inhalation, eyes, ingestion, and skin exposure.  NIOSH Pocket Guide is here.

Personal protection is a bit interesting. NIOSH recommends a full face respirator with P100 and organic vapor cartridges be used. The interesting part is that using this type of protection would allow exposure (based upon the protection factor) up to 15 mg/m3. Which, incidentally, is also the level as immediate danger to life and health (IDLH) = 15 mg/m3.

Some guides for dealing with this substance can be found here.

I was visiting a friend and in their neighborhood all of the curbs were cut for driveways (they were not poured for the cutouts). 

This might have saved some time for the carpenters forming & pouring the concrete. But it created additional work for the concrete cutters and the finishing of the driveways.

This lack of pre-planning created:

• additional time to cut the curb,
• dust (and silica, for sure),
• the use of additional water (hopefully) to control the dust,
• respirators (& cartridge filters),
• exposure to noise, dust, silica

I don’t know the circumstances why this occurred, but I wonder if the person planning the development thought of the exposures to other human beings?

ps. Sorry for my blogging absence. Have been on vacation! (for some of it)

There are only a few instances when you are not required to perform fit testing. The main reason not to perform fit testing is if the employees are wearing a respirator voluntary. (meaning: it’s not required)

So, how do you know if it’s required? It’s required when:

• You have overexposures to a substance (it’s required by OSHA to wear a respirator- so make sure you know, perform air monitoring), or
• If everyone is wearing a respirator during this task (it’s probably also required, just not formally- ie. spray finishing, or my favorite sanding drywall dust) or,
• If your company policy requires them to be worn (management says: it’s required to wearing a respirator during this task).

So, if you choose voluntary to wear a respirator and there is NOT a policy, or law, that says you HAVE to wear one then, you don’t need fit testing. (but you do need a few other things, Appendix D, etc.)

There is only one other exception:

• loose fitting hooded /helmet atmosphere supply respirators (when used in areas not immediately dangerous to life and health (IDLH))

Some employers choose to use these types of respirators because:

• the employee wears a beard
• it is convenient to use
• offers eye/face/neck protection
• it offers a greater protection factor
• it’s easier to don/doff (take on/off)

These guidelines for fit testing are different than medial testing before wearing a respirator, as spoken about here.

AIHA has released (2013) a white paper for guidelines on skills & competencies in silica specific to construction. It is a great outline for training your employees.

Some interesting points:

• Respiratory protection, and their respective assigned protection factor is mentioned. (Are you wearing the right respirator?)
• There is no mention of air sampling. Thank you. You do not need air sampling every-time, we already know it’s hazardous.
• They emphasize control measures for silica.

Another recent publication from IRSST in Canada explains the effectiveness of controls with regard to specific tools and where exposures are found in the industry. It has a lot of information, but if you are looking for the best method to control dust with a certain tool, it would be worthwhile to read the 108 page document.

The best resource for silica is silica-safe.org. You can create a plan for controlling it here. They have a database of tools & controls. Very handy. Someday soon we may see 3D printers able to make these dust controls and adapters for us at a moments notice. Until then, pre plan your task.

I’m easily impressed with welding and welders. Welding looks so simple, yet hard, dangerous and permanent.

When interviewing your welder, here are some questions to ask:

• What type of welding are you doing?
• What type of metal do you weld on? (mild steel, stainless, galvanized)
• Is there any coating on the metal?
• What type of flux is used?
• Where do you weld?, and then, “Where else?”
• Is there any ventilation in the area you weld?
• Are there any flammables in the area?
• Do you wear any PPE when welding? (ear plugs, respirator, leather)
• When do you use fall protection?
• Do you have & use welding shields?

What makes welding so difficult is the number of variables involved. The welding variables can change by the minute. Educate your employees on these dangers.

After the above questions, if the employee is agreeable, I ask some additional questions. These are the ones that provoke the best stories:

• What is the strangest things you’ve welded?
• Have you ever welding in a really small (confined) area?
• Have you ever welded with exotic metals? fluxes?
• What’s the worst thing you’ve welded on?
• Have you ever gotten sick from welding?

There are many, many more questions to be asked depending on the answers. The authority on this subject, Michael Harris, has written an excellent book on this subject, “Welding Health and Safety“(ISBN 978-1-931504-28-7). It is available from AIHA. It is VERY detailed, and money well spent if you do welding. I have taken his short course (all day) and I learned more than I ever thought possible, and I still can’t even weld!

There is a lot of confusion about N95 paper dust masks. And, it is confusing. The reason is because NIOSH has rated this type of equipment as a respirator. Prior to this, it was called a “comfort mask”. This name sounded better than calling it, “a worthless false sense of protection”. It is now called a, “dust mask”, or a “filtering face-piece”.

Here is what is required by OSHA if you wear this type of respirator (N95, or similar):

• Employees must read and sign Appendix D (of the OSHA respirator standard)
• Employees must clean, inspect, and store their dust mask

That’s it.

UNLESS you are wearing this because:

• Your employer requires it
• You have overexposures
• or, nobody “wouldn’t wear it”. (meaning: it’s an industry practice, and when when we do this XXX task, everyone wears this type of respirator– this is the same as your employer requiring it)

If  any of the above statements are true, then you have more to do. Here are links for more information:

Voluntary Use of respirators

Getting ready to wear a respirator

Professionally I do not recommend these type of respirators. Email me if you’d like to know why.

Before you can wear a respirator here’s what has to happen:

If you’re an employer and your employees wear a respirator, they are required to have a medical approval (Appendix C of OSHA respiratory standard). more details here.

The employee fills out the confidential questionnaire and then submits it to the medical provider of the employer’s choice. 95% (I made that # up) of the time, based upon the questionnaire ONLY, they give an approval to wear a respirator.

Occasionally, some employees are requested to come into the medical office to have a spirometry test performed, which tests for lung function. (a video of how it is done, cool accent included) This tests provides more information for the physician/nurse to determine if wearing a respirator will be too difficult for an employee to wear.

The cost for either test is usually pretty close to the same price… spirometry test, or not.

Here’s my suggestion:  Have every employee perform a spirometry test before wearing a respirator. This helps to guarantee they are capable of wearing a respirator. Maybe they forgot to list a risk factor, maybe they have a hidden serious lung problem, or, maybe they lied on the questionnaire so they can wear a respirator and keep their job.?

It is also beneficial for pre-employment screening, claims defense, and for a baseline in health. The specific results are usually NOT view-able by the employer, but they can be subpoenaed.

Controlling most of these types of exposures is really simple. If you know the job- and you know it will generate airborne silica = Pre Task Plan!

I wish Superintendents would enforce their project managers, or project engineers, to make a pre-task plan for every concrete/silica producing task. Then, (please don’t stop yet), review the plan once the project starts!

Below are two examples with different outcomes:

1. Cutting concrete block.

The pretask plan called for a garden hose with attachment(s) to wet the cutting area. Everything was perfect until the water was shut off. But, they improvised and found an electric water pump with bucket and recycled the water. It was a great outcome. What if the power went out? They could have used a Hudson sprayer.

2. Grinding plaster off a brick wall.

They built an enclosure and containment. They had a negative air machine with HEPA filters. They had a vacuum with HEPA filters, tyvek, 1/2 face respirator, eye protection, etc. But, as they worked the vacuum couldn’t keep up with the amount of dust generated by the 7 inch Bosch grinder. It was really dusty. They worked like this for days. No one onsite saw them because they were in containment. Unfortunately  the project is almost over and it could have been better. A simple shroud to the grinder, like this one (no endorcement) might have controlled the dust & silica. Sure, it might have been troublesome to find the exact one, and get a vacuum attachment, and have the extra weight, and ….

So, let’s talk to people about silica, talk about solutions, and then check to see if they’re effective.

Looking back at my lead in construction posts, I realized I did an inadequate job of summarizing why construction activities are dangerous when working with lead.

If you work in construction, here’s are the quick points as to why you should be concerned about lead.

• There has been A LOT of lead added to paint over the years. (it can vary 0.01% to upwards of 20%, and there’s no way to tell by looking)
• The activities we do in construction disturb this paint (some worse than others)
• You can be exposed to paint by inhaling it (if it is airborne), and if you happen to get it on your hands and you eat it (by transfer).
• The real concern is kids. (your kids, the kids who might be there after you’re gone, AND, the kids unborn (lead exposure can go from mom to baby)

The solution is simple (and, of course, more complicated as you dig in):

• test the paint to see if there’s lead in it
• if you disturb it, follow the rules (OSHA, EPA, HUD, City, etc.)
• train your employees (and measure the lead in their blood)
• prevent the dust from going everywhere (containment)
• measure the air to see if you are really screwing it up, or doing a good job.
• finally clean up. (the area, you, your hands, the perimeter) and dispose properly