Susan
Moir
University of Massachusetts Lowell
The most expensive
highway construction project in the world, the Central Artery/Tunnel (CA/T)
in Boston, Massachusetts, is scheduled for completion in 2005. Known as
the Big Dig, the project includes a new tunnel under the harbor connecting
Logan airport and interstate I-90, the Mass. Turnpike. The first section
of the tunnel, finished in 1995, is named for Boston baseball hero Ted
Williams.
Researchers from the Construction Occupational Health Program at the University
of Massachusetts Lowell have been conducting occupational health studies
on the Big Dig since 1992 under a mandate to improve health conditions
for workers in the regional construction industry. The research is part
of a nationwide consortium headed by CPWR – Center for Construction Research and Training,
the research, development, and training arm of the Building and Construction
Trades Department, AFL-CIO, and funded by the National Institute for Occupational
Safety and Health, part of the CDC.
Full-time staff researchers and student research assistants have spent
countless hours on site observing, interacting with workers and dozens
of contractors, and seeking ways to reduce musculoskeletal injuries and
exposures to silica. The seven miles of tunnel that make up the project
are constructed mainly of concrete. Concrete is mostly made of sand and
sand is silica. Drilling, chipping, cutting, or otherwise abrading concrete
produces dust containing airborne crystalline silica. When inhaled, this
can cause silicosis, a deadly lung disease. While the dangers of silica
have been known since ancient times, the COHP's research has shown that
workers doing concrete construction are exposed to a much higher level
of silica than was known in the past. To prevent silica exposure and future
cases of silicosis, contractors need to plan ahead and provide proper
protection to workers.
We first learned of this problem while watching the construction of the
Ted Williams Tunnel. We found workers on a scissor lift drilling approximately
17,000 holes in the concrete roof of the tunnel. We were told that hangers
would be epoxied into the holes to support the suspended ceiling ventilation
system. The workers doing the drilling were exposed to a mix of hazards
including silica dust and potential shoulder, neck, and back injuries
from using a heavy tool to drill overhead for hours at a time. It was
a very high hazard job.
We also noticed that the workers had added their own accessories, or "Bright
Ideas,"1 to make the job less hazardous. They had gone
to the hardware store and bought a household fan that they duct-taped
to the railing of the scissor lift to blow away the concrete dust that
was, as we now know, almost pure silica. They had also fashioned a pole
to hold up the drill and protect their shoulders and backs from injury.
We were told that this type of support is sometimes called a "soldier
pole" or an "inverse drill press."
This tunnel consisted of 13 pre-fabricated tube tunnel sections. Each
section had been lined with concrete before being sunk and connected on
the harbor floor. We asked why the holes had to be drilled after the concrete
liner had been constructed and why the holes were not designed into the
lining in the earlier formwork stage. Typical answers were that it had
to be done this way and that no one had really thought about the problem
in the design phase. Engineers on site told us that they had not been
able to plan for the holes because they did not know where they would
be needed until they began installation of the ceiling ventilation system.
We watched this job for more than two years and saw how hazardous and
difficult it was. We published a chapter in a book about the hazards involved.2
While we continued to raise questions about the hazards of the ceiling
ventilation system design, it took about three years to get a meeting
with the engineers who made the decisions about the designs.
At the meeting, the engineers said that we were not the only ones who
had raised questions about the design and that future designs had been
changed for reasons of health and safety, cost, and constructibility [ease
of construction]. As is often the case, the difficult and dangerous design
had also been very expensive. The new design eliminated the problem of
drilling holes for hangers by imbedding the supports for the ceiling ventilation
system in the tunnel roof during the concrete formwork stage of construction.
The first tunnel using the revised ceiling ventilation design, the I-90
Fort Point Channel tunnel, has been completed. According to Charlie Rountree,
safety and health manager for CA/T Managing Consultant Bechtel/Parsons
Brinckerhoff, the Ted Williams Tunnel ceiling ventilation system cost
about $55/sq. ft. The redesigned ceiling ventilation system cost about
$22/sq. ft. for a savings of approximately $33/sq. ft. in total installed
cost. Two additional tunnels under construction are expected to result
in similar savings.
Unfortunately, it is not possible to count the savings from injuries that
did not happen. However, as Rountree said, "We should always consider
safety and health, constructibility, and cost, in that order." There
is no doubt that redesigning the tunnel ceiling ventilation system prevented
some workers from getting career-altering musculoskeletal injuries and
life-threatening silicosis.
1 The COHP has published a series of "Bright Ideas," construction workers'
health and safety innovations on the job. They can be viewed on our website
at www.uml.edu/Dept/WE/COHP.
2 Brian Buchholz and Victor Paquet, Reducing ergonomic hazards during
highway construction: A case study of a tunnel ceiling panel assembly
operation. In: V. Rice, ed., Ergonomics in Clinical Practice, Butterworth-Heinemann,
Newton, Mass., 1998.
Worker drills
overhead one of 17,000 holes in tunnel roof for hangers for suspended
ceiling. The household fan added to blow way silica dust is taped to the
corner of the lift.
Workers install
suspended ceiling in tunnel.
This
document appears in the eLCOSH website with the permission of the author
and/or copyright holder and may not be reproduced without their consent.
eLCOSH is an information clearinghouse. eLCOSH and its sponsors are not
responsible for the accuracy of information provided on this web site,
nor for its use or misuse.
Susan Moir,
MSc, is former director of the Construction Occupational Health Program
at the University of Massachusetts Lowell.
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