Industrial Hygiene in Construction

This hazard is somewhat difficult to understand. There are number of reasons for the confusion, but the easiest way to explain it is to realize that:

Summary:

Diesel exhaust = Diesel particulate matter (DPM) = lots of different chemicals & particulates

AND: There is not a perfect way to measure the exact exposure.

The Long Story:

The term ‘diesel particulates‘ includes the following (not a comprehensive list):

• elemental carbon (the most reliable method for testing occupational exposure to exhaust, Birch & Cary 1996)
• organic carbon
• carbon monoxide (CO)
• carbon dioxide (CO2)
• hydrocarbons (PAH)
• formaldehyde
• oxides of sulfur & nitrogen

You can quickly see that these are very different substances, and to make it more confusing, you can change the amounts by:

• the fuel (on road/off, low emission fuel, biodiesel)
• the motor type
• the tuning of the motor (& dynamic versus idle), new motor restrictions
• scrubbers, etc.

In addition, there are not any well-established occupational exposure limits specifically for diesel exhaust. However, the International Agency for Research on Cancer has classified “whole diesel engine exhaust” as a carcinogen (cancer causing), so there is reason for concern. Most of the research and rules are in the mining industry, which uses a lot of diesel equipment and the exhaust really has no where to go.

• OSHA = none, but they have a hazard bulletin, and of course, some of the components have exposure limits
• MSHA = 0.4 mg/m3 for total hydrocarbons and 0.3 mg/m3 for elemental carbon
• Canada (CANMET) for respirable combustible dust (66% of respirable dust in mines is from diesel exhaust) = 1.5 mg/m3
• ACGIH = none (for now)
  • 1995 proposed 0.15 mg/m3 (for diesel particulate matter)
  • 1996 proposed lowering it to 0.05 mg/m3 (for diesel particulate matter)
  • 2001 proposed a different limit of 0.02 mg/m3,
    • but for elemental carbon and
    • said it was a suspected carcinogen
  • 2003 withdrew proposed limit- citing not enough scientific information

Bottom line:

• control the exhaust & where it goes (better fuel, better mechanical, scrubbers, ventilation).
• most exposures to diesel are below the (now retracted) ACGIH TLV of 0.02 mg/m3 (or 20 ug/m3) (Seshagiri & Burton, 2003).
• If you have a confined area, unusual concerns, or a particularly stinky situation; measure for multiple parameters (CO, CO2, elemental carbon and maybe NOx, and SOx). Compare these to their respective limits and classify the exposure (describe the conditions)

Do you smell dirty clothes in your indoor building? Do you suspect your heating ventilation and air conditioning system of causing the smells?

It might be what’s called, “Dirty sock syndrome”. Typically found in high humidity locations. A brief video overview can be found here (You Tube 2:03)

Lawrence Berkeley National Laboratory has good information on indoor air quality and how it affects people as they work. They also have some scientific information about how improving the indoor space (by ventilation, temperature, particles, etc) can create a better environment.

AIHA has a “Position Statement on Mold and Dampness in the Built Environment” (March, 2013).  It lays out the reasons to control moisture in a building, and some basic steps for remedy (spoiler: air sampling doesn’t usually help).

Bottom line: Check your coils before replacing your entire system. Replacing these might be cheaper. Or, sometimes they can be cleaned, but it is a strict protocol. One possible solution is here (I do not endorsement, or recommend this particular product/brand. Do your own research).

Unfortunately I have no problem finding an appropriate picture for this blog on Ebay. People are weird. Yuk.

The latest push from NIOSH is ridiculous, in a bad way. It’s titled, “Recognizing N95 Day” on September 5. I’ve written about these types of respirators before.

Let’s start with:

• NIOSH estimates 20 million workers exposed to airborne health risks
• N95 (s) are the most commonly used respirator
• NIOSH certifies all respirators. And, OSHA requires all respirators to be certified by NIOSH
• All certified respirators must have an “assigned protection factor”, which is a level of protection they are able to achieve
• N95 respirators are certified to provide a protection factor of “up to” 5 times the exposure limit

For the record, I am not disputing how NIOSH certifies respirators, or if these respirators can achieve a protection factor of 5 (5x the exposure limit). I will also add that in the healthcare setting (hospitals) these might have a useful role.

Here’s the problem:

• If you need a respirator, you would NOT choose a N95. They are terrible fitting.
  • To put it another way: if you had to work in an environment which had a dangerous airborne hazard, would you CHOOSE this respirator?
  • Or another way: “There is a chance this N95 respirator might protect you, wear this just in case”. (?)
• If you have fit tested these types, you know they are hard to fit, and at best, mediocre in their protection. At times it is hard to fit test a tight fitting 1/2 face respirator on someone who is clean shaven.
• N95 respirators are handed out (like candy) at construction sites for any task which “may be hazardous”.
• Let’s be honest:
  • these are “comfort” masks. AKA:  peace of mind, not for protection.
  • these are cheap. That is why most employers buy them.
• And, let’s mention:
  • exposure levels can vary (have you measured the worst case scenario?)
  • change out schedule? Do your workers wear the same respirators every day? Do they change them when they start getting hard to breathe?
  • facial hair (no one who is on a jobsite has this, right?)
  • there are knock-off N95 respirators which actually aren’t certified (they’re fake)

In this instance I wish NIOSH would spend money on training people to use the correct type of respirator. Or, how to adequately measure the hazards found at various sites.

As a quick review. If you need to wear a respirator, here are the proper steps.

It is officially summer and construction road crews & roofing is in full swing. Some projects require the use and application of coal tar pitch. Not only is it stinky, it is is hazardous.

Here’s some info:

• Uses
  • Roofing
  • Asphalt seal coating
  • Pharmaceutical treatment for psoriasis (scalp/skin condition)
  • Graphite industry (in the production of graphite)
• General
  • Coal tar pitch is actually a make-up of a bunch of different substances (maybe even 10,000 of them)
  • Contains lots of polycyclic aromatic hydrocarbons (PAHs) and other chemicals including: benzene, pyrene, benzo(a)pyrene, phenanthrene, anthracene
• Exposure
  • can be exposed by inhalation, ingestion (is this likely?), or exposure to skin, eyes
  • considered a carcinogen if the product contains more than 5% of coal tar
  • cancers include: skin, scrotal, lungs, bladder, kidney & digestive
  • increases your sensitivity to sunlight (easier to sunburn)
• Safety
  • Pick a sealant/coating that does not contain coal tar. A list of some can be found here.
  • Avoid inhalation & skin/eye contact
  • Train your employees. A sample safety SDS (MSDS) can be found here.
  • Wear the correct PPE.
  • Air sample to determine exposures. OSHA has a method (58).
• Resources
  • OSHA Coal Tar Pitch Volatiles
  • CDC Coal Tar Pitch Volatiles

Can we measure an exposure accurately with just one sample? (statistically, no.) Also consider: Can we measure a “worst case” scenario and be OK for the rest of the project? (again, hypothetical question)

There was a blog post, here by Mike Jayjock, which reminded me of how silly our data points (aka industrial hygiene sample results) are in the big picture of statistics.  I’m slowly reading a book titled, “Control Banding” by David Zalk who is with Lawrence Livermore National Labs. The CDC also has a section on control banding here.

Another side of this is a common practice we all perform called Risk Analysis. There is much on the subject, but essentially it’s similar to triage at an emergency room. What is the easiest, best thing you can do: given what you have available and what you are able to muster?

Too often (myself included) we perform air monitoring for a specific situation and use that information as the gospel-truth. Well, this might be like living in the United States and never traveling. We meet a very nice person from the Ukraine. They seem very typical Eastern European and have a thick accent, but are they really like everyone in Russia? Is this person typical? Are they exactly like every other person from Russia?

This type of stereotyping is the same as taking one sample and drawing conclusions about all exposures. You might be right, BUT…you might be wrong.

There is a fun app you can download called, IH DIG by Adam Geitgey (Apple & Android).  This app illustrates the importance of using statistical tools, rather than guessing. (It’s a game)

Sorry I do not have many answers in this post, just a lot of questions.

If you really have an indoor air quality and mold/fungus issue, it usually stems from moisture. I’ve talked about it before, here. The simplest answer is to find the water. Control the moisture and you inevitable will control the future indoor air quality concerns. Once you have found (and controlled) the water, then it is time to repair the damage and lingering water (which can’t evaporate).

The issue is: where does moisture come from? Well, it ‘can’ come from almost any direction:

• from above (rain, roof vents, skylights)
• from below (moisture in flooring, concrete)
• walls (penetrations into the exterior, or windows and flashing)
• out of thin air (relative humidity)

The EPA has written a new document titled, “Moisture Control Guidance for Building, Design, Construction and Maintenance“. As a contractor, how do you know when the clean up is too much to handle? I’ve written a bit more about it here.

The best time to clean up a moisture issue was yesterday, but the second best time to clean it up is today. Don’t let it sit, it usually doesn’t get any better.

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.

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)

Let me first say that I am still learning about this hazard and why it is so dangerous.

Polyurethane foam is used as an insulating material. More info on it’s uses here. The danger is when you spray it (think: expandable type), or apply it, or cut/remove it after it’s cured. The danger is in the off-gassing.

There are two main considerations:

• the process of applying the foam
  • spray type
  • quantity?,
  • ventilation?
• the type (manufacturer/brand/type) of foam
  • curing rate,
  • type of hazard, etc.

What we know is that there is a hazard. AND, this hazard may not effect everyone, OR, it may not effect you until some time has gone by. But, some of the chemicals in these types of products include:

• isocyanates (people can die, and get asthma), and it is a OSHA Emphasis Program, and OSHA page here
• amines
• VOCs (volatile organic chemicals)
• flame retardants (PBTs)
• Blowing agents (EPA link)

There is a huge potential for work related asthma when using these types of products. And, even contact with the skin can trigger an allergic response/asthma attack. If you have employees working around this type of product and have ANY respiratory symptoms (or asthma), please have them checked by an occupational medicine doctor.

Control of this hazard should include:

• PPE for employees (respiratory, eye, & skin protection)
• ventilation during application
• ventilation during off-gassing & curing (can be 72 hours)
• control plan for spills, cutting & demo
• control plan for employee/occupants with asthma

The EPA has a quick reference card here (hat tip to Tom), and more detail from the EPA on how to control the hazard here. The Spray Polyurethane Foam Alliance has free training here (haven’t checked it out though), and be mindful that anyone can be an instructor (good & bad).

If you’ve ever won an award before, sometimes getting the award rarely equates to anything lasting (other than your increased ego). However, in construction nowadays, safety awards are HUGE! This is especially true if you are competitive bidding (or plan to in the future). I know companies who have received jobs & project  based upon one (or several) safety awards they have won. Of course they had other things going for them, but the safety award was the tipping point.

I am talking about company safety awards, not safety awards for being safe (see my earlier post, about safety incentives).

I really don’t think it matters where you get the award.

• Could be a OSHA SHARP, OSHA VPP, a regional/local conference (here’s an example, and here),
• an association award for safety (AGC, CURT, ABC),
• an insurance award (workers comp, your general liability carrier),
• safety program award,
• trade association (HVAC, Landscape, Union) or go for
• Safety non-profit (National Safety Council), ASSE, local section, or
• LEED and sustainability award (I know, not exactly safety-related).

Heck, create your own award! If you’re a GC, or a specialty contractor, why not give awards to your subcontractors or general contractors if they do an amazing safety work, or provide innovation? Print off your own certificates. Or, at the end of your project, ask your owner/GC if they will recommend and/or give you an award for the safe work you’ve performed.

Here’s an example of a construction website’s awards: Russell, James (no connections). Here’s a similar article from EHS Today.