Industrial Hygiene in Construction

For better, or worse, the silica rule has been delayed, again. This delay is for an extension of the public comment period, which goes until December 12, 2013. Public hearings are set to begin on March 4, 2014.

Find OSHA here, with links to my previous post. A NPR story from February, 2013.

My views on this rule haven’t changed much: It’s still a mixed-bag. There are still overexposures to silica (see my pictures from the last 3 weeks). However, will the new rule change the behavior?

• Overexposures are still happening
• Silica deaths have decreased over the past (without the new rule)
• Will the small employers (the ones who typically offend the most) comply? Or just wait to be cited?

But, my overwhelming thought is this:

• Any new rule will generate “noise” for the subject of silica. And, that’s a good-thing.
• This will drive:
  • compliance
  • changes
  • innovation
  • discussions
  • awareness

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)

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.

Yes, there can be airborne silica in the concrete when you are chipping up motar & tiles from a concrete base. This week a friend told me about his neighbor. He is a self-employed tile setter. He has worked in the industry for 20+ years. They just discovered he has cancer and will have the upper portion of his lungs removed.

Go here for more information. NPR article on silica rule delay.

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.

You probably already knew this. Risk changes over time.

As we start to measure, and value, loss we immediately want to minimize it. However, it’s an unobtainable goal. “Zero losses”. Really? It’s not actually possible, you know (at least in the long term).

Look at this graph of the number of deaths in the US over the years due to silica. In 1968 we had approximately 1,000 deaths. Now, in the year 2005, we are less than 200. Yet, OSHA wants us to lower the exposure limit.  (I am personally not opposed to it – but I am open to debate about it, really)

Our world is becoming smaller. But, you already knew this, too.

To give an example, look at what happened in Bangladesh on November 24/25, 2012. Meanwhile in the US, we were watching football and eating leftover turkey.  Over 100 people died due to safety concerns that turned into a fire. This country is going through what the US experienced pre-1970. Other countries have similar problems.

I suppose living in the US is a yet another reason for thanksgiving. Yes…, But.  What can you do to make the biggest impact? I don’t have the answer, but, I am open to suggestions.

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

For people who work with asphalt everyday, this may be a obvious statement: Silica is in asphalt.

There are two areas where this might be of concern:

1. During the mixing of the asphalt there is usually some ratio of rocks that are added to the product. The size of these rocks is where safety personnel should have concerns. If they are adding the smallest fraction of rock to the mix, you may have airborne exposures to silica. This size of rock is called P200 (or, using a 200 sieve screen to get anything less than 200 parts per inch). Usually this is seen during the transfer of rock from the loader or from the belt conveyor.
2. The other method of exposure to silica in asphalt is if you cut it. Rocks may contain silica. When asphalt is cut, you incidentally cut through various rocks (contained within the asphalt). Silica (and dust) is released during the cutting. Please use water when you are cutting asphalt. Direct the water at the blade.

While doing airborne silica sampling I noticed this industrious employee using not one, but TWO hands free mobile devices. This guy can multitask!

I think flip phones might be making a comeback.