King County is using the latest in environmental-protection technology to
remove lead-based paint from the Green River Gorge Bridge east of Black
Diamond.
This labor-intensive project has
closed down the bridge for five months. It
is scheduled to reopen in late October.
The bridge is currently being sandblasted to remove the old paint. Once the
288-foot-long bridge has been stripped, it will be repainted with three coats
of a non-toxic paint. Painting the steel elements of the bridge will protect it
from rusting and increase its useful life.
Removing the paint and preparing the structure surface is time intensive.
The federal Environmental Protection Agency (EPA) has strict guidelines for any
project involving the removal of lead paint. The process must meet stringent
guidelines for containment and disposal of the old paint, as well as
ventilation requirements for worker safety.
The worker-safety regulations are extensive. The painting contractor must
develop educational and medical programs to prepare workers for the job. All
employees must be trained in the hazards of lead-based paint, as well as
cleanup techniques and other procedures to ensure they follow all federal
Occupational Safety and Health Administration regulations.
Employees are subject to medical examinations before, during and after the
project. The contractor must also provide a decontamination area so workers can
shower and put on clean clothes before leaving the project work area.
Because the bridge is perched almost 200 feet above the Green River, King
County worked with Long Painting, the painting contractor, to build a
containment "box" that can be moved in sections across the bridge. This box is
32 feet wide, 40 feet long, and tall enough to surround 50-foot-deep bridge
truss.
The box prevents the old paint, blasting sands, and other debris from being
released into the surrounding environment. It is also hooked up to a negative
pressure system that brings in fresh air for the workers, while removing the
dirty air through a series of ducts and filters. After traveling through the
filters, the debris is packaged into sealed 55-gallon drums.
"It’s like a big vacuum cleaner," said Sam Bellah, King County’s inspector
for the Green River Bridge project. "We’ve found this is the most effective way
to handle steel structures covered by lead-based paint."
The county first used this technology in 1997 to remove old lead paint on
the Raging River Bridge in Fall City.
