PEL (Perm Exp Limit)


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:n95 box

  • 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.

n95 box2

This has to be one of the coolest types of cutting. Raw obliteration of metal.

As you know, hexavalent chromium (Cr6) is generated when the metal, chromium, is heated. Cutting this metal with a plasma torch is an easy way to heat it up quickly.  We performed air monitoring on one employee performing plasma cutting on #304 stainless. Luckily the employee was wearing a 1/2 face tight fitting respirator (and skin protection due to the body readily absorbing Cr6) and we found exposures at 36% of the exposure limits (they were within the acceptable limits). This employee was able to stand away from the cutting due to the machine he was using. He did not do this task all day and no engineering controls (ventilation) was used. 

****Caveat: Please do your own air sampling. Conditions and environment may not be similar to your environment, and they can change rapidly. One sampling event rarely indicates all conditions. We’re talking about people’s health!****Keep in mind welding safety

plasma cutting

And a close up of the cutting machine without the motor & tracks:

cutting bevel

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 happeningsilica street2
  • 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

silica street1

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.

 

OSHA helps

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)

OSHA lead table 1

 

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 cameraoverexposures. 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.

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 respirator

  • 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.

helmet respirator

Chromium in it’s elevated valence state, called Chromium 6, or hexavalent chromium is a known carcinogen and sensitizer. From a toxicological point of view, it has a really interesting exposure to disease path.

I’ve mentioned it before, but recently NIOSH reduced their suggested limit from 1.0 µg/m³ to 0.2 µg/m³ (80% reduction for you math wiz’es).  They base this on eye & skin irritation, respiratory damage & lung cancer. Yikes.

OSHA has listed their exposure limits, along with other’s recommended limits here.

The take-away from this reduction is the serious nature of Chromium 6. hex chrome cleaningIf you are dealing with this hazard, you should take more than just a little precaution. Even if your prior air monitoring data is below the Action & Exposure Limit, continue  to document and verify your employees are well below the regulatory & recommended limits. As you know, hexavalent chromium is a skin hazard and can be absorbed easily into your body. I would also suggest performing wipe samples (area & skin) & decontamination in areas where there is work activity with hexavalent chromium.

For most construction companies, investigate these areas:

  • welding (any stainless steel?) See this earllier post, also here.
    • And, OSHA has a new Fact sheet on welding & hexavalent chromium here.
    • Washington’s OSHA (L&I) has a great page on the hazards during welding here, including training videos. (so cool!)
  • hardfacing on equipment. See earlier post.
  • Bridge painting – (or painting with chromates) OSHA’s new safety bulletin is here.
  • Electroplating – OSHA’s safety bulletin is here.
  • Anytime you heat, or work with chromate painted surfaces.
  • Portland cement when working with it wet and on your skin. NIOSH has some information here. hint: Try adding ferrous sulfate to lower the Cr6.

And, if you don’t work in construction, but live in Garfield, NJ, you might have to pull your toenails out to prove you aren’t exposed to hexavalent chromium.

From what I have seen, there are not a large amount of formaldehyde exposures in construction. However, there is A LOT of formaldehyde used in construction materials. Formaldehyde can be dangerous at levels undetectable by your nose. And, the symptoms of exposure are nondescript (irritant & tingling of eyes, nose, respiratory tract).

Here are some products that may contain trace (or more) amounts of formaldehyde:

  • resins in plywood, MDF, CDX, particle board/fiber board
  • garage doors
  • drywall
  • roofing
  • glues / mastics
  • paint/coatings
  • carpets
  • insulation (spray in and batting)

I believe the reason we do not see high exposures is due to the limited duration of exposure, and the open-aired nature during the construction. Some exceptions are warehouses with large storage areas of particle board/MDF. (I have found exposures in these areas)

The OSHA exposure limit for formaldehyde is 0.75 ppm (action limit of 0.5 ppm, and short term limit of 2 ppm). However, this may not be low enough, based upon other standards (ACGIH says 0.3 ppm, NIOSH 0.1 ppm)

Another major issue with this hazard in construction is once the space is occupied.

  • Once construction is done, the space may be sealed up, heated, and additional curing can occur.
  • This may release more formaldehyde, and also NOT allow as much to escape (by dilution ventilation).
  • Compounding this issue are the type of occupants in the building. Are there children, non-working adults, immunocompromised individuals, sick, or elderly occupying this space? The OSHA standards are NOT protective for these types of people.

I do not forsee this type of sign being posted immediately after new construction.

formaldehydeOn the plus side, someone has discovered that plants may help reduce formaldehyde & VOC levels in homes. Horticulture Science Kwang Jim Kim, et.al

 

NIOSHNIOSH has just recommended a new exposure limit (REL) for hexavalent chromium. The new limit is 0.2 ug/m3 as an 8-hour TWA. If you remember, the OSHA PEL is 2.5 ug/m3 (8-hour TWA). SO, if you’re good at math, you can see this is A LOT lower.

The reasoning for this level is they have found a lung cancer risk (get this) EVEN AT 0.2 ug/m3. They recommend bringing airborne levels below this limit for lung exposures.

As I’ve described before, exposures are not limited to just inhalation. Dermal contact is a big concern.

If you have any hexavalent chromium at your facility, or stainless steel (welding, welding2hardfacing, etc.) you need to do more than just air sampling. You need a comprehensive program including wipe samples, medical monitoring, etc. This may not be a specific OSHA rule for your facility.  However, these exposures are something you must manage.

 

Many times an IH is called upon to determine the cause of a person’s ailing symptoms. For example, an employee might complain of congestion, irritability, bloody nose, etc. Someone has decided it might be from their exposure at work.homer sick

The practice of industrial hygiene is difficult to apply to an individual. What I mean is, this field of study was developed due to serious health concerns over a population of people at work. This is essentially how science works, you take a population, study it, find the differences, then make conclusions.

Trouble occurs when you try this backwards. If the same person (as example above) complains of congestion, irritability, bloody nose- can we assume they must have exposure to lead dust? Not usually. We must obtain other clues.

What industrial hygienists try to do in these instances is rule-out the possible over-exposures. Sometimes we can measure for chemical exposures to see if it might be of concern. But even then, it’s not fool proof. Below are a few issues which make it complicated.

  • exposure at work? job? extracurricular activities? home?
  • person might have autoimmune disease and gets sick easier
  • sampling is not feasible
  • sampling is somehow screwed up (by IH, lab, mail carrier)
  • exposure is through food, clothing, etc.

Even with these fallacies, there are things an individual can do to narrow down their ailments:

  • create a log. time, type of symptoms, pain scale, others experience/smell, food eaten
  • change things and see if it improves/makes it worse
  • research – but do it right. Look at the items you use, check the SDS

 

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