Airport_Business_December2019-January2020 - 12

SAFETY MATTERS
AUTHOR Joe Petrie

SILICA
SAFETY:
WHAT AIRPORTS NEED TO KNOW
Recent OSHA rules mean new ways to tackle
pavement maintenance at airports to protect
workers.
A FEDERAL change in silica rate exposure is
transforming the way airports maintain concrete
surfaces.
OSHA lowered the silica exposure
rate for general industry in 2018 from
50 micrograms per cubic meter to 25
micrograms. While concerns about silica
have been present for decades, airports
may not realize how these new rules
applies to them.
"This amount is so small that if you
were to stand in the center of a football
field on a 15-foot ladder and take a single
pack of Saccharin and open it and shake
it into the wind, that dust carried over
the entire football field would exceed
25 micrograms per cubic meter," said
David Rigsbee, CEO of Chemtek. "It's
a significantly small amount of material."
Silica dust isn't visible. Because it's
so small, it can easily enter a person's
respiratory system and embeds itself in
the lower part of the lungs. Exposure
can eventually cause COPD, cancer
and Silicosis, which is similar to Black
Lung Disease.

Milling also creates silica dust and workers
can be protected taking measures outlined
in construction rules under OSHA standards.
CHEMTEK

Silica is a nationwide issue, but
Rigsbee said there's more concerns in the
Northeast where a lot of granite materials
are present and in the West where a lot of
sand-type materials are present.
"Silica is ubiquitous. It's everywhere,"
Rigsbee said. "It's in the sand, it's in the
sidewalks, the runways, the taxiways and
anything that contains concrete."
Airports are required to do exposure
assessments to check silica levels during
a time-weighted eight hour work shift.
If workers are exposed to elevated silica
levels more than 30 days per year, it's
considered a high exposure.
Airports can't dry sweep for FOD
under the new regulations due to the
amount of dust it creates, Rigsbee said.
Although airports are now required
to add water for sweeping operations,
he said water alone doesn't have a low
enough surface energy to wet silica dust.
"Silica dust in its native environment
without any wet water control can
travel hundreds of feet," he said. "Once
you wet it, it can only travel a few
inches, it drops to the ground and you
can no longer breath it. If you add a
material like our Nesilex product to
the water, then it changes the surface
energy of the water and in the process
causes the silica to be wetted and
therefore completely controlled."
The preferred method of mitigation
are engineered controls like vacuums
that force the air through HEPA filters,

OSHA rules state workers
must be limited to the
exposure to silica dust.
CHEMTEK

water or doing other types of activities
that don't produce silica dust.
During activities like milling or
cutting concrete, Rigsbee said airports
can meet the requirements by following
the rules set under the construction
category of the OSHA rule.
During other activities, airports
are required to do personnel exposure
testing and area exposure testing on a
periodic basis.
"They have to measure sweeping,
sawing milling, using a jackhammer
and any activity that has the potential
for generating silica dust," he said. "Then
they're required to write a safety plan
that eliminates exposure by engineering
controls and if engineering controls can't
control the exposure, they're required to
provide respiratory protection and they
have to medically monitor employees." 

12 \ AIRPORTBUSINESS / DECEMBER 2019/JANUARY 2020
Airport_Business_December2019-January2020

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