American Oil and Gas Reporter - August 2018 - 84

SpecialReport: Hydraulic Fracturing Technology

Tools Minimize Silica Dust Exposure
On June 23, the U.S. Occupational
Safety and Health Administration began
enforcing a tighter standard for exposure
to respirable crystalline silica (RCS) as a
precaution against debilitating and often
fatal lung and kidney diseases. Detailed
in 29 CFR 1910.1053, the new standard
applies to hydraulic fracturing operations
and limits workers' exposure to an eight
hour time-weighted average of 50 micrograms per cubic meter (µg/m3).
The standard requires employees to
measure silica dust exposure in areas
where it is likely, says Joseph Kraham,
director of industrial hygiene for AIRIS
Wellsite Services, an industrial hygiene
consultant and dust control equipment
provider. Unless silica dust exposure
consistently falls below the action level
of 25 µg/m3, he says employers must:
* Write an exposure control plan;
* Demarcate and regulate areas where
silica exposure may occur;
* Post compliant signage nearby to
warn employees about silica dust;
* Establish effective engineering controls and work practices to minimize exposure;
* Assess exposure at work sites and
continue monitoring it until it stays below
the action level;
* Put employees in medical surveillance programs; and
* Keep records of test results.
Even on sites where boxes or silos rather

than "sand king" systems handle sand transportation, Kraham warns that it is easy to
exceed the 50 µg/m3 permissible exposure
limit (PEL) when evaluating representative
personal samples. He estimates that 74 percent of sites have at least one employee exceed the PEL and 88 percent have at least
one employee exceed the action level.
Sites that meet the limit may neglect
other components of the rule, such as the
warning sign requirements, Kraham says.
"The standard mandates proper housekeeping procedures," he adds. "To collect
spilled silica sand, employers must use a
HEPA vacuum or wet methods. Sweeping
or shoveling the sand or using compressed
air can create dust that workers might
breathe in."
While the standard's engineering control requirement does not take effect until
2021, Kraham encourages employers to
implement controls as soon as possible
rather than trying to meet the exposure
limit through workplace practices alone.
"Workplace practices can be difficult
to enforce," he observes. "For example,
when we go on sites that mandate respirators, we often see employees wearing
them inconsistently or improperly." He
points out that respirators only work for
people who are clean-shaven.
A High Bar
Ideally, Kraham says employers should
try to get exposure below the action level

To meet the Occupational Safety and Health Administration's limit on employees'
exposure to respirable crystalline silica, AIRIS Wellsite Services generally recommends
installing vacuums around sand transfer points to capture dust before it can reach
employees. The company cites years of data showing that vacuums work well and have
a minimal effect on operations.

84 THE AMERICAN OIL & GAS REPORTER

of 25 µg/m3. "If the employer can demonstrate that its procedures and processes
will effectively keep silica dust below the
action level, the standard no longer applies.
That means the employer can stop monitoring exposure levels and putting employees under medical surveillance, which
is a huge cost-savings," he explains.
To prove the standard should not apply,
Kraham says employers must test below
the action level twice in a row on occasions
at least seven days apart. He cautions
that exposure must stay below the level
under any foreseeable circumstances.
"That is a high bar to meet, but is a
challenge worth tackling," he argues. "In
theory, the permissible exposure limit of
50 µg/m3 represents the maximum an employee can be exposed to every day without
suffering permanent harm. But as more
data become available, we may discover
that the limit should be lower. Today's
limit for RCS is half what it used to be,
and the limit for asbestos has changed
multiple times since its introduction."
Kraham says employers who go the
extra mile not only will do right by their
employees but also protect themselves from
future liabilities. He predicts that managing
silica dust exposure will become more important as proppant intensities increase and
operators experiment with progressively
smaller meshes, trends that may increase
total silica dust generation exponentially.
One of the most effective ways to reduce
RCS is to minimize the number of times
sand moves from one device to another,
says Katie Sallee, AIRIS Wellsite Services'
vice president and controller. She explains
that each transfer point gives the proppant
an opportunity to generate RCS.
"Modern sand handling systems have
cut the number of transfers, but they
still have areas where RCS forms," she
says. "The industrial hygiene assessments
we have performed suggest that even
the newest and most modern proppant
handling systems still need to be augmented with an effective engineering
control to stay under the action level
consistently."
In most applications, Sallee recommends
as an effective engineering control vacuums
that are installed around transfer points to
collect RCS before it enters the work environment. "These vacuums have a small
footprint, a minimal effect on operations
and the flexibility to work with almost

American Oil and Gas Reporter - August 2018

Table of Contents for the Digital Edition of American Oil and Gas Reporter - August 2018