This PowerPoint was presented to the OSHA Advisory Committee for Construction Safety and Health on November 27, 2012 by Dr. Bruce Lippy, Director of Safety Research for CPWR. The presentation was given in conjunction with one by Dr. Kristen Kulinowski of the Science and Technology Policy Institute to provide the committee with a background on the potential risks posed to construction workers by applications containing nanoparticles.
I would like to address four questions:
- What nanomaterials are found in construction?
- What do we know about exposure to nanoparticles in construction?
- How are the hazards being communicated to workers?
- What is CPWR planning to do about nanomaterials as the NIOSH-funded National Construction Center?
What nanomaterials are found in construction?
A recent study found carbon nanotubes in the airborne particles at Ground Zero
This presentation is focused on engineered nanoparticles
There are many promising applications in construction, but limited commercialization at this point
Lee, Mahendra & Alvarez (2010)
“Cost and the relatively small number of practical applications, for now, hold back much of the prospects for nanotechnology.” -Nanoforum Report: Nanotechnology and Construction, November 2006
There is more activity in Europe, mostly in coatings, cement and concrete
- 94 available products identified
- reduced weight of concrete with silica fume*
- increased strength and elasticity of concrete
- improved weathering of exterior surfaces
- biocidal surfaces for walls of surgery rooms
*Aggregate of amorphous SiO2 nanoparticles
Broekhuizen et al. 2011
These tiles contain nano-titanium dioxide
We would like to test exposures
One roof can oxidize NO2 from 10,800 miles of driving, according to the manufacturer
Emaco NanoCrete patching compounds does not contain nanoparticles.
From the manufacturer: “Nanotechnology does NOT mean nano-sized particles: We do not use any nano-particles in our cement formulations.”
These hydrated silicates are nano-structured; they have nano-sized holes
NIOSH has begun an HHE looking at Aspen Aerogel insulation, another nanostructured product
Mark Methner, NIOSH
What do we know about exposure to engineered nanoparticles in construction?
We know construction workers may be at risk
“Inhalation of manufactured nanomaterials during coating, molding, compounding, and incorporation can pose a respiratory health risk to workers.” - Lee, J., Mahendra, S. & Alvarez P.J. (2010, July).
We do have corroborating data on ultrafine exposures showing respiratory issues
Apprentice from UA Mechanical Trades School in Landover, MD, 9/12
Photo courtesy eLCOSH
Sampling was conducted onsite for several real processes in 2009
(Broekhuizen et al, 2011)
- Mixing Nanocrete mortar
- Applying spray-on TiO2 coating onto glass
Particle sampling during mixing of 6 bags of Nanocrete mortar (Broekhuizen et al, 2011)
"Workplace measurements suggest a modest exposure of construction workers to nanoparticles (NPs) associated with the use of nanoproducts."
NIOSH chose mass-based REL over counting with electron microscopy
- NIOSH Method 5040
- Counting protocols haven’t been developed, although ASTM committee is close
REL of 7 µg/m3
elemental carbon (EC) as an 8-hr TWA
37-mm quartz-fiber filter
Nanoparticles Have Almost No Mass
Courtesy Larry Gibbs
Large particles bias mass measurements
If you’re carrying a grocery bag full of cantaloupes, you’re not going to notice a handful of grapes.
Courtesy L. Gibbs
Transmission electron microscopy is the gold standard and will be used in CPWR’s work
TEM allows several measurements
- Chemical composition
- Particle count
- Particle length and diameter
NIOSH image of MWCNTYou do the analysis:
Do these particles appear similar?
Bulk product sample
How are the hazards being communicated to workers?
Photo courtesy eLCOSH
"80% of the workers’ reps and 71% of the employers’ representatives were not aware of the availability of nanomaterials and were ignorant as to whether they actually use nanomaterials at their workplace."
- 2009 Survey response from 28 construction workers and employers in Europe (N = 144) Broekhuizen et al. 2011
We haven’t been doing a great job communicating the hazards of standard industrial chemicals
- Hazard Communication: A Review of the Science Underpinning the Art of Communication for Health and Safety Sattler, Lippy & Jordan, May, 1997
Sattler, Lippy & Jordan 1997 review of hazcom literature for OSHA was the only one for a decade
- University of Maryland contract with OSHA. Report at: www.osha.gov
- Accuracy of technical information was a problem
- Most studies were based on reported preferences, not behaviors
- Populations studied were students not workers
Comprehensibility of MSDSs was not good
Literate workers only understood 60% of the health and safety information on sample MSDSs in three different comprehensibility studies:
- Printing Industries of America, 1990
- Kolp, Sattler, Blayney, Sherwood, 1993. Am. J. Ind. Med
- Phillips, 1998
Findings from a newer review of the literature did not show improvements
Nicol et al. 2008, Am. J. Ind Medicine
Lippy Group reviewed NIOSH collection of nano MSDSs
- N = 49 MSDSs
- Reviewed all of the MSDSs
- 33% did NOT identify the nano component
- 52% did NOT have any cautionary language
Large surface area in relation to particle size enhance physical and chemical properties (nanosilver)
Most (62%) just referenced PELs and TLVs for the macro size
- 32% percent indicated nothing
- Only 6% used cautionary language about using PELs/TLVs
MSDS for Carbon Nanotube
The GHS changes will be a big improvement, but OSHA can do more using the existing SDS format
- ANSI Section 16 “Other Information” is the key.
- Useful risk information about nanoparticles can be included in Section 16.
- OSHA could create an eTool helping SDS developers with the appropriate language
What is CPWR planning to do about nanomaterials as the NIOSH-funded National Construction Center?
Two CPWR Initiatives
1. Identify specific construction-related products and create an inventory
Nano-phase silica-filled epoxy adhesive SEM image (scale bar = 100 nm)
Wilson Center has 1317 products, produced by 587 companies located in 30 countries (03-10-11)
The Europeans have created an inventory of construction products
- FIEC represents construction employer organizations in 29 countries
- EFBWW represents 75 affiliated construction unions in 31 countries and represents a total of 2,350,000 members
Broekhuizen et all. 2011
Newly revised site for nano!
Second CPWR Initiative
1. Identify specific construction-related products and create a registry
2. Identify applicable control technologies currently in the CPWR Construction Solutions database and measure their effectiveness with nanoparticles
Will these control nanoparticles in construction?
Airtec Jet-Rotary Hand-Held Concrete Milling Machines
Pentek Air-Powered COMPACT-VAC High Performance HEPA Vacuum
Conventional controls should work with nano
CPWR will be working with a firm called EPI Services that has a test chamber
Controlled area where construction products will be tested.
Photo courtesy EPI Services, Inc.
Along with its own website and distribution system, CPWR will work with other organizations including yours