Industrial Hygiene in Construction

There are pieces of equipment used in construction which are VERY difficult to control their noise generation; open cabs of equipment, drilling machines, impact drivers/drills, and some mechanical devices are the first to come to mind.

Modifying equipment to control the noise is better than handing out ear plugs. But, before you modify the equipment, does your company have a “Buy Quiet” program? NIOSH & CPWR released some info graphics which can help start you down this road to considering noise levels when purchasing new equipment.

Before modifying equipment to control noise consider:

• Does the manufacturer have a “factory approved” modification already available?
• Are there any liability considerations if you make this change?
• Have you discussed the modifications with:
  • The manufacturer? Engineers?
  • Operator?
  • Mechanics?
  • Scope of work?
• How much noise reduction are you hoping to achieve?
  • remember noise is logarithmic, so a reduction of  1 dB is achieving a lot…
  • but not much practical difference in regards to operations
• Measure noise before and after, both static and dynamic

I’m still startled by how many construction companies have not started a hearing conservation program. However, I do know why: we don’t see a lot of worker’s compensation claims from this injury (we still see them, but not in the numbers we think we should).

Recently I was asked this question: My company is strictly a general contractor. We do not have field employees, only Superintendents, Estimators, Project Managers, Project Engineers, etc. Do we need a hearing program?

Here’s why I think you should start a hearing program:

Start one for risk prevention, maybe not for overexposure to noise.
Most hearing loss claims are around $20k, and the cost of a program is about $15/year/employee. And, in some states, if you are the last injurious employer, you have to prove you WEREN’T the cause of the loss. (So, do noise monitoring/dosimetry semi frequently)

Other reasons:
• it set’s a good example for your subs – when your subcontractor is making noise, it’s hard to tell them they need to start a program when you don’t have one at your company.  Call it ‘credibility’.

• you can roll it into your company’s total worker health (TWH) / health promotion/ wellness program – even if you aren’t required to have it. Wouldn’t it be nice if your company took steps to make sure you still have your hearing?

• if you’re checking their hearing; and they have losses, you can intervene – this might be a big one for construction employees. How many construction workers have noisy tasks? Shooting, hunting, motorcycles, concerts, cutting wood, drag racing, mow their lawn? They may have hearing loss outside of work. If you’re monitoring their hearing, you can maybe influence their behavior while doing these activities.

Obviously starting a program can take time to manage, but there are mobile units which can provide most of the work. And, if you have a workforce above 50-70 employees, it might even make sense to purchase your own booth.

Noise has some interesting health effects. Most people assume the worst that can happen is you will lose part of your hearing. However, a recent (March, 2014) study in Injury Prevention by Girard, et.al, concluded that those employees exposed to loud noise (above 100dBA) were admitted to hospitals more frequently, and at risk for other injuries.

Some other known health effects include (from Medscape & WHO):

• fatigue
• impaired concentration
• behavioral changes
• irritation
• impaired academic performance
• interrupted sleep (during sleep times)
• changes in endocrine & autonomic nervous systems
• increase in heart rate, blood pressure, vasoconstriction
• sexual impotence
• neurosis
• hysteria

Noise is a simple subject, but there are many factors which influence noise exposure to individuals. Some include:

• The individual: age, prior exposure
• The noise: loudness (dB), type of noise (Hz), distance from noise
• Time: exposure vs. non-exposure time per day

More information on how to control this hazard in construction can be found here.

And, as a bonus, the Journal of the Acoustical Society of America has published a review of the top Smartphone Sound Measurement Apps..  The winner (most accurate) was SPLnFFT, at only $3.99. A close runner up was SoundMeter by Faber. Another summary review is here, and here.

I titled this post, “hazards of drywall”, but it encompassing most of the common hazards of plaster, mud, gypsum, wall-hangers, tapers, and acoustic employees.

1. Corrosive drywall.

   I have not dealt with this subject on a personal level. However, AIHA has a new guidance document titled, “Assessment and Remediation of Corrosive Drywall: An AIHA Guidance Document“, which is a clarification of an earlier white paper document from 2000, titled, “Corrosive Drywall“. The danger is from a specific type of drywall which was imported from China. After installation it is known to emit sulfide vapors, which corrode copper (electrical wires), and can give off a sulfur smell (HT to JeffH in Ohio).

2. Asbestos in mud/plaster.

   Be aware, some older buildings (pre 1980s) may have asbestos in the mud compound or plaster (not as common). This will be a concern if you are performing demo on these walls. Info here.

3. Silica (dust) in joint (mud) compound.

   Some types of silica I have found to have silica. This can be an issue when sanding. AND, if you install drywall like me…you do a lot of sanding. More information from an earlier post can be found here. NIOSH has some suggestions too.

4. Leaded sheetrock. If you are installing (or demo) leaded sheetrock, you NEED to protect yourself. Airborne levels of lead can approach the exposure limits, even during installation. More info here.
5. Lead in paint. If you’re tying into existing plaster/drywall and there’s paint, you need to know if there’s lead in it. Sanding on the paint is a good way to be exposed. More info here.
6. Ergonomics. Hanging the wallboard takes a toll on your body after 20 years (or less). Not to mention sanding. Washington OSHA (L&I) has a good demo.
7. Noise. Cutting steel studs, powder actuated tools (there’s lead exposure too, you know).
8. Skin hazards. Cutting, but also dermatitis from prolonged exposure to dust.
9. Eye hazards. Dust, carpentry, etc. Working overhead is an easy way to get falling items in your eyes.
10. Falls. Last on my list, but certainly not the least. Scaffolding, working from ladders, and using stilts, to name a few.

It’s sad to say, but many construction companies have not yet started a formal hearing conservation program. Their solution is to purchase the best earplugs, for the lowest cost, and give them away like candy.

As I’ve mentioned before: Sometimes OSHA’s rules are protective (meaning: you will be safe) and other times they are really not on par with the health research. Hearing loss and OSHA’s method of measuring noise are NOT protective to employee health (your hearing). For the best method of measuring noise, look to the recommended guidelines of the ACGIH. In order to get the exact parameters, you must purchase their Guide to Occupational Exposure Values (TLVs) booklet. It hasn’t changed (at least for noise) for a few years, but it is still the most up to date on health for your hearing. Here’s a summary of some differences:

• Exchange rate (how noise doubles and is averaged over time)
  • OSHA uses 5, ACGIH uses 3 >>which means noise doubles every 5, or 3 dB increase
  • this makes a BIG difference in your accumulated average noise level (TWA).
• Exposure Limit, or Criterion Level
  • OSHA says 90 dBA, ACGIH says 85 dBA
  • Doesn’t seem too different (-5), but remember noise is logarithmic and it’s measured different by OSHA & the ACGIH

NIOSH also has some guidelines, which are very similar to the ACGIH.

There are some strong benefits to having a hearing conservation program. Here are some examples and suggestions for bettering your own program.

• You can be recognized
• Win an award. 
• Have less (or even better: none) hearing loss claims
• What about just hearing soft noises? kids? hunting? sports? the TV?

If you have worked in construction for any period of time, you know how loud it can be, and how much exposure is out there. Don’t assume working in this industry that hearing loss will to happen to you. Do something about it. Here’s a presentation from CDC/NIOSH a few years back on how to start.

Hair growth for your ears! This type of hair growth is different than the hairs which grow longer as you get older… 

The problem with most types of hearing aids, cochlear implants, and other types of enhancements is that they only amplify the body’s ability to hear. I talked about a type of pill we someday might be able to take that helps, here.

Research has found a way to regrow the hairs in your ear…well, at this point, only in mice. But, in theory, you could put these hair growth cells in the part of your ear where you have the most damage…and, well, it might help!

The summary article is here. The original article is here. And, to nerd-out, here is the research paper.

As you might be aware, there is a loudness of noise which your ears cannot be protected against. Your body’s system of preventing the sound waves from entering your ear are just too much for it to handle. As the noise (sound pressure) hits your inner ear the bones convert the physical energy (noise) into a chemical & neurological process so you are able to hear. Ear plugs and ear muffs are not sufficient enough to protect against the amount of noise exposure.

However! Sometime in the future we might have a pill to prevent this type of hearing loss.

Researchers have found that the chemicals, D-methionine, ebselen & N-acetylcysteine, battle chemical stress on your ears.  We are still a long way from being able to take a pill to avoid hearing loss. They must go through more testing and the FDA approvals.

But, isn’t that cool!?

If you operate a ready-mix plant and have concrete trucks, you are aware of this process. Once a year (hopefully, only once) a person must climb into the drum of the ready-mix truck and chip off excess concrete. What happen during regular use, is that some concrete hardens, which usually sets-up over and around the blades. Access into the drum is by either the 3×4 hole in the side, or down the chute.

Yes, it is a confined space (def’n: 1. large enough to enter, 2. not designed for occupancy, and 3. limited entry/egress).

Here are a list of the possible hazards:

• silica dust (from chipping concrete)
• noise exposure
• hazardous atmosphere (curing concrete uses up oxygen, which we DO need BTW)
• slipping hazard (drum is round inside)
• heat stress (if you’re trying to do this activity in the summer)
• eye hazard (chipping)
• electrical hazard (if you’re using water & have an electric hammer)
• lock out / tag out (if the truck drives away, or if the barrel starts turning)

There are many resources available (see below). Some things to keep in mind; ventilation (fans, etc) to control the airborne silica dust are usually not effective (too much dust versus exhaust). Water controls are best, but you must limit the amount of water and the direction of the sprayer. I suggest looking at what others have done.

Keep in mind, if you perform this activity you will need (as a company):

• respiratory program (medical, fit test, written plan)
• confined space program (multi gas meter, written program, attendant?)
• lock out /tag out policy or procedures
• training (for each of the above, and for this specific activity)

At this point I know what my contractor-friends are thinking…I will subcontract this out!   ha. If you do, please make sure your sub is doing it right.

Resources:

Georgia Tech – good presentation & guidance

Georgia Tech/OSHA – Safe Work Practices (in Spanish too!)

Teamsters H&S hazards & controls

Illinois DCEO – Consultation on ready mix cleaning

Yes. If you are in construction, I recommend it. Here’s why:

First, the rules. OSHA does NOT have a specific construction standard for hearing conservation. Why does this matter? Well, the current OSHA rules state that if you have 1 day (that’s only one day) of average noise level above an average of 85 decibels A-weighted (dBA), called the Action Limit, you are required to start a program. Obviously noise levels vary on construction jobsites. I’d guess that most projects have at least one day of levels above 85dBA’s.

And, these particular OSHA rules are terrible. Well, they are terrible if you care about your hearing. (see my earlier post). The rules are simply not protective enough. If you are exposed to noise for 8-hours a day at 90 dBA (the OSHA average exposure limit) you WILL have hearing loss (this is without hearing protection). Does that seem like a very protective rule?  I’ve heard talk about them changing it, but…I doubt it will ever happen.

Second, let’s consider cost vs. reward. To start a hearing conservation program you must measure your employees hearing , called audiometric testing (and do a few other things). It costs approximately $20/employee to do this per year. Compare this with the average claim (of hearing loss) cost of around $20,000. So, if you have 20 employees, and it costs you $400/year…it takes about 50 years to pay yourself back for NOT starting a program. ($20,000/400= 50 years)

Third, consider your employees. Having their hearing checked may seem like a hassle and a worthless exercise, but, some will appreciate it. I’ve found that employees like to know how they are hearing. It’s good if your employer cares how well you hear. It’s also a yearly reminder in hazard awareness to noise.

Because in construction, we know there’s noise!

If you’re dead-set on NOT having a program, you’ll need documented noise dosimetry for each employee, job task, and possible overexposure above 85 dBAs. It is possible  for a construction company to avoid having a program, but you have the burden to prove there isn’t noise. Call your favorite industrial hygienist for help.

I get the best questions from employees as I’m setting them up to wear a dosimeter. (FYI- this does not really apply to sound level readings, only dosimetry)

• Why do I have to wear the monitor (dosimeter)? Can’t we just place it in the middle of the area?

Ideally we want the dosimeter to measure the individual exposure. Many factors influence the average noise level, including work practices, location (sound bouncing & dampening), height, proximity to others, equipment, etc.

• What is the dosimeter actually measuring?

A dosimeter measure the sound pressure level, measured in decibels A-weighted, dBA (usually). It can record this level and average it (usually) for every 1 minute period. The amount of information it gathers is staggering…and confusing.

• What if we work a longer shift (more than 8 hours) will the results of the noise monitoring be the same?

Yes, the results are (usually) given as an average. So, in theory, if you measure the noise for 15 minutes and it is the same for the next 7.75 hours, it should be the same. However, if you work more than 8-hours a day OSHA actually decreases the amount of noise you can be exposed to. They have a table (G-16)  that attempts to explain it.  If you know the average level of noise (say it’s an average of 95 dBA 8-hour TWA), then you can determine the time you are allowed (answer: 4 hours).

• How often should noise monitoring be performed?

There is not a specific rule from OSHA on how often you must monitor. However, the guideline is yearly.  Or if/when significant changes occur “which might effect the results of this testing” (I always use this statement in my reports).

• Which individual employees should have their noise level measured?

It is best to let the industrial hygienist make this determination (there are several good reasons). If you are just starting out, they will often choose an average, or those who might have the highest noise level exposures.

• I’m wearing hearing protection, why don’t they take that into account when they determine the average readings?

Your exposure is determined without regard to the specific type of hearing protection used. If you are wearing the wrong type of hearing protection, or if it is worn incorrectly, you could still have this exposure.