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Steve Neilson, CIHU.S. Department of Energy

Thomas Jefferson Site Office

DOE and DOE Contractor Industrial Hygiene Meeting2012 Industrial Hygiene Conference and Exhibition, Indianapolis, IN

June 18, 2012

Construction Project Silica Exposures and Observations at the

Thomas Jefferson National Accelerator Facility

Thomas Jefferson National Accelerator Facility (TJNAF)

• 800 Employees, 1300 User Community• 6 GeV Continuous Electron Beam Accelerator• 3 Experimental End Stations for Nuclear Physics

Research• Free Electron Laser (FEL) Facility• SRF Institute• Center for Theoretical and Computational Physics

Theoretical Physics

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Construction Projects

12 GeV Upgrade Projecto $ 310 Million Dollarso Combination of Civil Construction and Equipment Upgrades

• New experimental end station, tagger, and related infrastructure• Additional cryomodules to the existing accelerator• Upgrades to existing experimental end station detectors

o Civil Construction Phase was Completed January 2012

Technology, Engineering and Development Facility Project (TEDF)o $ 73 Million Dollarso Combination of New Construction and Renovation

• Technology and Engineering Development (TED) Building (complete)

• 30,000 SQF addition to Test Lab• Renovation of over 90% of the 96,000 sq. ft. Test Lab (former NASA Synchrotron facility)

o Projected Completion Date is March 2014.3

Event #1

• Tasko Removal of a wedge shaped section of the new concrete floor slab to

accommodate pouring a slab between the new tunnel and the existing Accelerator tunnel floor

• Work Environmento Tunnel cross section dimensions roughly 8’ wide x 7’tall, in a cul-de-sac

configuration (temporary wall to accelerator arc is located about 30’ away)

o 12 hour shifts

• Tools and Techniqueso Jackhammers – 3 different sizeso Garden hose wetting manually applied to chisel impact zoneo Hurricane Fans

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Work Conditions

• The area was visited during the conduct of a Joint Construction Safety Walkthrough

• Work had stopped momentarily for a scheduled break, so jackhammering had not been active for some number of minutes prior to arrival.

• Visible suspended dust was present along a fairly long section of the new tunnel

• Garden hose and wet floor indicated the workers intent to suppress dust

• Hurricane fans staged in various locations along tunnel• Due to the suspended concrete dust concern, the General

Construction Contractor agreed to suspend work until respiratory protection was applied and air sampling was conducted

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Outside view of the Tagger Tunnel

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Tagger Tunnel from the Inside

Note the area sample being collected with a nylon cyclone attached in the top left corner of the photo, and the

placement of the hurricane fans

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Breathing zone and area air sample collection

Workers outfitted for the collection of a breathing zone sample for respirable silica.

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Jackhammer Operation

Water was continuously applied at the jackhammer point of impact

Event #1 Monitoring Results

• Close agreement between area and breathing zone air sampleso Percent crystalline quartz = 35% o JLab area sample TWA = 0.679 mg/m3o Contractors BZ sample TWA = 0.66 mg/m3

• 12-hour adjusted PEL and TLV for respirable crystalline silica (quartz) o PEL = 0.18 mg/m3 o TLV = 0.03 mg/m3

• Respirator MUC of 0.3 mg/m3 (half mask tight fitting respirator with HEPA filters) would not provide adequate protection for the 12 hour work shift.

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Event #2

• Tasko Concrete floor slab removal because new slab was poured too thick for

future alignment with sky bridge between new and old building.

• Work Environmento Interior stairwell landing

• Tools and Techniqueso Jackhammero Manual wetting of slab and jackhammer chisel area with water sprayo Manual load-out of rubble in 5 gallon bucketso Wearing disposable, filtering facepiece respirators

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Event #2 Monitoring Results

• Area sample collection by Lab CIH indicated collection location is considered to be representative of breathing zone exposure.

(no sampling initiated by GC)

o Percent crystalline quartz of bulk dust = 26%o Respirable crystalline silica area sample TWA = 0.078 mg/m3 (exceeds ACGIH 2005 TLV of 0.05 mg/m3)

• Respirator protection factor could not be applied since the worker had not been fit tested, trained, or medically qualified for the filtering facepiece respirator (N-95) worn at the time of this activity.

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Similarities• Indoor work activities over multiple days of

exposure• Workers exposed above the TLV • Jackhammering• Wet methods• % crystalline silica in the same general ball park• Attempts at ventilation control having limited

beneficial effect.• Lack of work planning

o One Contractor was essentially completing final actions before demobilization (construction phase was all but finished)

o Other Contractor was trying to make up schedule from the rework (pouring initial slab too thick).

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Additional Construction Related Silica Observations

• Two different events, separated by a couple days• Both were dry brick cutting outdoors • In at least one case, the saw was equipped and

designed for wet cutting• In both cases, the work was not performed in

accordance with documented work plans that required wet cutting

OUTCOMEContractor issued $10,000 fine by the Laboratory for failure to perform work in accordance with safety requirements

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Additional Corrective Action Taken (not comprehensive)

• Mandatory silica hazard training for all construction workers• Activity Hazard Analysis documents audited for construction

contractor• New work planning form (permit) created for work that has

silica exposure potential• Lab developed a resource document for subcontractors to

highlight where the 2005 TLV’s are more restrictive than the PEL’s

• Master Spec contract language revised on silica exposure controls and monitoring expectations

• Laboratory Subcontracting Officer’s Technical Representatives (SOTR’s) were given silica awareness training and specific responsibilities on evaluating work having silica exposure potential

• Additional oversight at construction projects by Lab ES&H staff17

Collective Challenges For the Department

• Don’t presume your contractor understands the impact of 10 CFR 851, or the hazards of silicao Moving from conventional notion of “dust” to the respect necessary

with “silicosis/carcinogen” o The TLV and PEL are worlds different o Construction contractors will incorrectly presume that any wet

method is satisfactory o A bucket of paint comes with a MSDS, a concrete slab doesn’t

• Effectively imparting Lessons Learned information to construction contractors (GC and their lower-tiered subs)o One of the sentiments held after event #1 was this particular

contractor was on their way out the door – good riddance and we won’t have to worry about that again. Obviously it was later confirmed that this vulnerability was shared with other on-site construction contractors

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Challenges (continued)

• Don’t immediately defaulting to respiratory protectiono Observation of the dry brick cutting tasks are indicative of a generally

used approach to simply put on a dust mask, which is simply not compliant, and may not be enough.

o There are commercial, off-the-self solutions such as local exhaust snorkels for drilling, jackhammering, and sanding. Control at the point of application may also have a side benefit of managing overall housekeeping

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Challenges (continued)

• What if the subcontractor is not initially compelled to sample activities of concern? o One option is to collect your own area samples

• Advantage – non-invasive and shouldn’t interfere with work • Disadvantages

a) Area samples may not be good surrogates for BZ exposures for compliance – could be contentious with the

subcontractor. b) The Lab becomes a crutch. It’s the subcontractor’s responsibility as the employer under 851, and they must be held accountable for evidence of the effectiveness of work controls

o Better Alternative – Incorporate plain contract language to emphasize the subcontractor has full responsibility for providing evidence of exposure control effectiveness, but the Lab retains the right to collect their own samples for evaluating contract compliance at their discretion. This should reduce the likelihood of the subcontractor filing claims because you negatively impacted their schedule and cost.

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Commercially Available Local Exhaust Systems Exist