Industrial Hygiene in Construction

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.

Let’s clarify: You are a working adult. You are feeling symptoms (of some sort). And, you think it’s from something your exposed to while at work (in construction). This could include, but will not, the flu-bug. Below is a list of the most common construction illnesses.

Most Common Construction Illnesses:

1. Upper respiratory
   • could be from silica, drywall, dust, asbestos, nuisance dust, chemicals (I won’t even try to list all of them)
2. Skin (dermal, dermatitis) damage –
   • From: concrete, abrasion, chemicals
3. Eyes
   • mostly from things that get into the eye.
4. Cumulative trauma (ergonomics) or inflammation
   • repetitive motion, over a day hurts, imagine this for years
5. Burn (heat or chemicals)
   • Usually around hot work like welding, but this can occur when using certian chemicals
6. Hearing loss
   • cumulative trama to the ears when exposure is above about 85 decibels for any extended period of time.
7. Poisoning– General or systemic
   • From: poison ivy, stinging needles, dog bites, bees, etc.

This list may vary depending on many things including what type of construction you are in; GC, heavy, civil, specialty, etc.  I put this list together to get a picture of where we see illnesses. However, as previously mentioned, and, everyone knows, the FOCUS FOUR is really where most injuries occur in construction.

We have seen the most prevention of illness due to one single device:

the back support.   ha. just kidding, of course.

Industrial hygiene (aka occupational hygiene) focuses on occupational-related diseases due to many reasons.

Have you considered, at your home, maybe even as you sleep, you might be exposed to something hazardous? Below are seven possible hazards in your home (related to IH):

1. Radon. It comes from the ground and they say it causes cancer* (*some people question this toxicological data). You must perform a test to know if you have hazardous levels.
2. Formaldehyde. If you have a newer house you have 2 things going against you: 1. your house is tightly built (no air leaks and limited fresh air) and 2. more particle board (recycled wood) was used in construction. Also, many furniture contains multidensity fiber wood (MDF) which off gas formaldehyde. Again test for it to know if you have dangerous levels.
3. Lead. Is your house built prior to 1978? It probably has leaded paint. Any remodeling might distrupt it and you can expose your kids to lead.
4. Isocyantes. (HDI, TDI, MDI, and others) Can cause asthma & respiratory issues. If your house was insulated with spray foam (polyurethane type) it needs to off-gas for awhile before you move right in.
5. Asbestos. Causes cancer when airborne. If your house was built prior to 1980, you might have asbestos in your pipe insulation, popcorn ceiling, etc. Be sure and have it checked prior to remodeling.
6. Mold. Respiratory diseases.
7. Cleaning products. The symptoms can vary depending on the type of chemicals in the product. Use the recommended gloves, eye protection and respirator, if necessary, while cleaning with chemicals.

Do not be overly concerned about any one thing. Simply test and make any necessary adjustments. However, do keep in mind that most health recommendations for substances relate to normal working adults who go home to a non-hazardous place. There can be issues if you are either: not considered in the general population of healthy workers and, you go home to a place that isn’t free of additional hazards.

When performing air monitoring it can be useful to take multiple samples on the same individual throughout the day. Here are some reasons to change out the filters:

• build up of dust on filter – can cause overloading
• break-out the exposure data. Morning versus afternoon, or by job tasks, or the physical area the employee is working in, controls vs. no-controls, etc.
• if you question the employees motives. If you think the employee might skew the results, multiple samples might give you better control- or at least tell you if one is way-out-of-line.

Once you have your data results, how do you combine them?

If you’re taking particulate (dust, lead, cadmium, silica, etc) and you have the concentrations (from the lab) here is what to do.

1. note the time (in minutes!) and the concentration results (mg/m3, ug/m3, etc) for each sample
2. multiply the time and concentration for each – then add each number together
3. finally, divide the above number by the total number of minutes sampled. This is your time weighted average (TWA).

Simple?! Yes. …And it’s really easy to make a mistake too. Check your math, and then eyeball the results and see if they make sense logically.

Here’s an example:

Andrew took three samples during one shift while Shelley was rivet busting through leaded paint. The first sample (118 minutes) was reported as 6.8 ug/m3 of lead, the second was for 245 minutes and had a concentration of 18 ug/m3. The last sample was taken for 88 minutes and was reported a level of 29 ug/m3. The overall results is 17.2 ug/m3 for the total time sampled. (Side: if you sampled for their entire exposure, and they worked longer hours, you could add those hours (assuming zero exposure) into the final time-in step three)

See the math below:

As continued from my earlier post, and, a little more to the point…What do you ACTUALLY do when you think you have mold?

Test the air! Perform air monitoring for as many different things as you possibly can. Just kidding. Actually, DON”T do this. (caveat: if you plan legal action-then you might do this)

If there is visible mold/fungus. The first step is to find the water.  In order for mold to grow it must have moisture and a place to grow. There are many places to look including; the roof, windows, seams, ANY penetrations into the building envelope, from below (seeping up), water lines, A/C units, condensation, etc. You absolutely cannot fix the damage or test the air until you stop all sources of water.

Second step, assess the damage. The general rule of thumb is if the damage has altered the substrate (ie, the wood is damaged) then you need to replace it. If it is only on the surface, it may be possible to just clean, dry and seal it. If it is more than 10 square feet of damage, consider hiring a qualified specialist.

Thirdly, repair & replace any concerned areas.

Fourthly, dry it thoroughly, then seal it. Look into methods to increase the ventilation into this area.

Fifthly, inspect and finish. A good visual inspection is far better than air monitoring. If you can still see mold growing, you’re not done.

Finally, clean the ducting & surrounding areas. Please choose a qualified inspector. For some reason this industry attracts lots of bogus contractors.

Air sampling vary rarely gives you any information that will assist you in these steps. Some other good information about indoor air quality and mold from California can be found here.

I was requested to perform training for a management team (VPs, Estimators, Superintendents, PMs, PEs) on health topics. The request was specific: asbestos, lead, silica and mold/ IAQ (indoor air quality). I was given an hour, which is hardly enough time. However, the audience took well to it.  I was impressed with the questions and discussion that followed the training. Here are some highlights from that training that the management team adopted as policy. Most of these can be considered tips for good management of IH programs.

ASBESTOS:

• Before the project begins we will have (in writing) an asbestos survey
• As a contractor you typically sub the abatement work
• Employees need awareness training at some level (usually class IV)
• Any asbestos found is to be sampled (by an inspector) and NOT to be touched

LEAD:

• Before the project begins we will have (in writing) a lead survey of the building
• As a contractor we must manage lead on the project (no abatement usually)
• Any lead found on the jobsite WILL BE controlled
• Employees need awareness training – site specific
• Lead ACTIVITY (s)  must be characterized and assessed for possible exposures – and further steps

SILICA:

• There is/will be silica on our jobsite
• We WILL take steps to control the silica exposure when it occurs
• Employees will be trained as to the dangers of silica

MOLD/ IAQ:

• We will manage any mold/fungus found onsite
• We will have a plan for how we handle the situation as we arises
• We will be sensitive to any health or mold/fungus concerns