EMERGING RISKS: VOC
OFF-GASSING OF COMPOSITE PRODUCTS (SUCH AS WIND TURBINES); INHALATION OF
STYRENE VAPORS DURING THE MANUFACTURE OF WIND TURBINE BLADES
There are a number of hazards associated with the manufacture of the wind turbine blades and other components, especially the inhalation of styrene vapors during the coating of the blades. Following the record number of fatalities of workers in 2011, the U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA) and American Wind Energy Association (AWEA) recognize the value of establishing a collaborative relationship to foster safer and more healthful American workplaces. To that end, OSHA and AWEA formed an “Alliance” to provide AWEA’s members and others working in wind energy industry maintenance and operations with information, guidance, and access to training resources that will help them protect the health and safety of workers, particularly by reducing and preventing exposure to fall, electrical, and crane hazards, and understand the rights of workers and the responsibilities of employers under the Occupational Safety and Health Act. OSHA also officially focused its attention onto the wind energy industry, meaning more inspections and enforcement actions against violators of worker safety laws.
The participants
intend to work together to achieve the following outreach and communication
goals:
- To develop information on the recognition and prevention of workplace hazards, and to develop ways of communicating such information (e.g., print and electronic media, electronic assistance tools, and OSHA’s and the AWEA’s Web sites) to employers and workers in the industry.
- To speak, exhibit, or appear at OSHA’s or AWEA’s conferences, local meetings, or other events.
- To share information among OSHA personnel and industry safety and health professionals regarding AWEA’s good practices or effective approaches through training programs, workshops, seminars, and lectures (or any other applicable forum) developed by the participants.
OSHA’s Alliances
provide parties an opportunity to participate in a voluntary cooperative
relationship with OSHA for purposes such as raising awareness of OSHA’s
rulemaking and enforcement initiatives, training and education, and outreach
and communication. These Alliances have proved to be valuable tools for both
OSHA and its Alliance participants. By entering into an Alliance with a party,
OSHA is not endorsing or promoting, nor does it intend to endorse or promote,
any of that party’s products or services.
The turbine installation and maintenance fall accidents are very similar to the accidents occurred during the installation, disassembly or maintenance of telecommunication towers. Nineteen workers have died in communication tower accidents since 2013, a sharp rise from recent years. In 2014, over 20 workers have fallen to their deaths during cell tower operations. OSHA has announced new changes in how it polices the industry, including tracking what cell carrier or tower owner subcontractors had been working for when accidents occurred.
Blade Maker Cited 8th Time in 4 Years
Thursday, April 28, 2011
A wind turbine blade
manufacturer with a history of federal safety violations, including some
related to a 2010 death, is now accused of having employees work in a confined
space filled with excessive levels of styrene.
The Occupational
Safety and Health Administration has issued 11 serious, repeat and willful
citations and proposed $136,500 in penalties against LM Wind Power Blades Inc.,
of Grand Forks, ND.
LM, formerly known as
LM Glasfiber, is already contesting three OSHA cases, including the one
involving the fatality, at the same plant. OSHA records also show four closed
cases with LM since 2007, including three at the Grand Forks facility.
“We take this very
seriously and will continue to collaborate with authorities to ensure we
maintain a safe working environment for all our employees,” an LM spokeswoman
said in an email Thursday (April 28). “At this point, however, it is premature
to say what our response will be.”
Chemical Exposures,
Confined Space
The new allegations
stem from an October 2010 inspection. Over two days, the agency said, the
company allowed employees to remain at work inside the confines of a giant
wind-turbine blade amid exposures to styrene that reached 2,195 parts per
million (ppm), triggering air-quality alarms.
Styrene is a
hazardous chemical used in fiberglass production; OSHA’s short-term exposure
limit is 600 ppm; for an eight-hour shift, it is about 100 ppm, an OSHA
spokesman said.
Supervisors allowed
the work to continue for hours, despite air-quality readings showing excessive
exposures, and did not evacuate the confined space as required—willful
violations, OSHA said, that demonstrate “intentional disregard” for the law or
“plain indifference” to employee safety and health. Those two citations carry
$70,000 in penalties.
“The employer is well
aware of OSHA requirements and has continued a pattern of failing to comply with
them,” said Tom Deutscher, OSHA's area office director in Bismarck. “Despite
having been cited for similar infractions in the past, the company continues to
place workers in harm's way by allowing hazards to exist.”
OSHA said LM workers
did not have proper protective equipment for working with styrene. “Severe
chemical burns to the body were reported to the employer,” the agency said.
Repeat, Serious
Violations
In addition to the
willful violations, OSHA issued five repeat violations for alleged failure to:
- Provide adequate respirators “for conditions immediately dangerous to life or health”;
- “Purge or ventilate” the atmospheric hazards within a confined space;
- Prevent employee overexposure to styrene levels exceeding the time, weighted average and ceilings limits; and
- Implement engineering controls to ventilate the confined space.
Four serious
violations also were issued for allegedly failing: to:
- Provide appropriate personal protective equipment;
- Conduct effective confined space monitoring;
- Retrain employees when required; and
- Maintain an accurate count of entrants in permit-required confined spaces.
A repeat violation
exists when an employer has been cited for the same or a similar violation
within five years. Serious violations reflect a “substantial probability” of
death or serious injury from a hazard about which the employer knew or should
have known.
The company has 15
business days to accept or contest the violations.
OSHA Record
LM Wind Power,
founded in 1940 as a wood furniture company in Denmark, is the world’s largest
manufacturer of wind turbine blades, with 13 production facilities on three
continents. In April 2010, the company changed its name from LM Glasfiber.
The North Dakota
facility opened in 1999 and employs several hundred people.
LM has a history with
OSHA, with violations and allegations that include spray finishing hazards,
combustible materials, fall protection and respiratory issues, noise and dust.
These cases have been
closed:
·
In
2008, LM paid $17,400 in fines (reduced from $29,000) for four serious and one
repeat violation related to styrene exposure, lack of respiratory protection
and other violations at the Grand Forks facility.
·
In
April 2010, the company paid $1,500 (reduced from $6,000) for two serious
violations (reduced from four) and one other-than-serious violation at the same
facility.
·
Earlier
this month, the company paid $2,500 to settle one other-than-serious violation
(reduced from serious) at the plant.
·
The
company was also cited in 2009 for violations at its plant in McBain, MI.
The company also is
currently contesting several open cases involving the Grand Forks plant:
·
Last
July, a 42-year-old plant worker was fatally crushed between two pieces of
equipment. Witnesses said Joseph Francis Schaff, a father of two young sons,
was working about 10 to 12 feet up on a scissor lift when he was struck from
behind by a separate lift system that ran along rails fixed to the top of a
concrete wall.
LM is contesting
three serious and one willful violation and $92,000 in fines issued in that
case.
·
The
company is also contesting two citations issued in October 2008. That fine has
already been reduced to $850 from $2,975, and one serious violation has been
reduced to other-than-serious.
·
Finally,
the company is appealing two serious citations (reduced from three) and a
$3,000 fine (reduced from $7,875) issued in April 2007 for spray finishing
hazards and other issues.
Occupational
exposures to styrene vapor in a manufacturing plant for fiber-reinforced
composite wind turbine blades.
OBJECTIVES:
A utility-scale wind
turbine blade manufacturing plant requested assistance from the National
Institute for Occupational Safety and Health (NIOSH) in controlling worker
exposures to styrene at a plant that produced 37 and 42 m long fiber-reinforced
wind turbine blades. The plant requested NIOSH assistance because previous air
sampling conducted by the company indicated concerns about peak styrene concentrations
when workers entered the confined space inside of the wind turbine blade. NIOSH
researchers conducted two site visits and collected personal breathing zone and
area air samples while workers performed the wind turbine blade manufacturing
tasks of vacuum-assisted resin transfer molding (VARTM), gelcoating, glue
wiping, and installing the safety platform.
METHODS:
All samples were
collected during the course of normal employee work activities and analyzed for
styrene using NIOSH Method 1501. All sampling was task based since full-shift
sampling from a prior Occupational Safety and Health Administration (OSHA)
compliance inspection did not show any exposures to styrene above the OSHA
permissible exposure limit. During the initial NIOSH site visit, 67 personal
breathing zone and 18 area air samples were collected while workers performed
tasks of VARTM, gelcoating, glue wipe, and installation of a safety platform.
After the initial site visit, the company made changes to the glue wipe task
that eliminated the need for workers to enter the confined space inside of the
wind turbine blade. During the follow-up site visit, 12 personal breathing zone
and 8 area air samples were collected from workers performing the modified glue
wipe task.
RESULTS:
During the initial
site visit, the geometric means of the personal breathing zone styrene air
samples were 1.8 p.p.m. (n = 21) for workers performing the VARTM task, 68
p.p.m. (n = 5) for workers installing a safety platform, and 340 p.p.m. (n =
14) for workers performing the glue wipe task, where n is the number of workers
sampled for a given mean result. Gelcoating workers included job categories of
millers, gelcoat machine operators, and gelcoaters. Geometric mean personal
breathing zone styrene air samples were 150 p.p.m. (n = 6) for millers, 87
p.p.m. (n = 2) for the gelcoat machine operators, and 66 p.p.m. (n = 19) for
gelcoaters. The geometric mean of the personal breathing zone styrene air
samples from the glue wipe task measured during the follow-up site visit was 31
p.p.m. (n = 12).
CONCLUSIONS:
The closed molding
VARTM process was very effective at controlling worker exposures to styrene.
Personal breathing zone styrene air samples were reduced by an order of
magnitude after changes were made to the glue wipe task. The company used
chemical substitution to eliminate styrene exposure during the installation of
the safety platform. Recommendations were provided to reduce styrene
concentrations during gelcoating.
The Evolution of Infusion to Circumvent the Problems
Posed by Styrene Regulation
The use of the
resin infusion process has grown significantly in the 25 years since fiberglass
boatbuilder/composite materials distributor Seemann Composites (Gulfport,
Miss.) introduced SCRIMP (Seemann Composites Resin Infusion Molding Process). In Europe, manufacturers of marine and
industrial composites will have to look at infusion and other closed molding
processes, due to the increased regulation of styrene,” observes infusion
researcher John Summerscales, an associate professor of composites engineering
at the University of Plymouth (Plymouth, U.K.). Currently, styrene exposure
limits vary by country in Europe, from 20 to 100 parts per million (ppm), with
the U.K. maintaining the latter. However, in 2011, the European Chemical
Industry Council (CEFIC) proposed that the derived no-effect level
(DNEL) for worker inhalation exposure to styrene should be 20 ppm (over an
eight-hour, time-weighted average) and that this DNEL might be used to
harmonize styrene exposure limits across the European Union.
The American
Composites Manufacturers Assn. (ACMA) has responded to similar pressure in the
U.S. by proposing an occupational exposure limit (OEL) of 50 ppm, which it says
will mean “working toward a target eight-hour average exposure of approximately
35 ppm.”
Resin infusion is an
extremely effective way to meet these new limits. For example, during a 2009
National Institute for Occupational Safety and Health (NIOSH) walk-through
survey of the LM Glasfiber (now LM Wind Power) wind blade facility in Grand
Forks, N.D., the lowest personal breathing zone measurements for styrene were among
the 21 workers performing infusion, all at less than 5 ppm.
Indeed, wind blade
manufacturers migrated to resin infusion and other closed mold processes
between 2000 and 2005 (see Figure above), with production of large blades (length
>30m/98 ft) reportedly now split between infusion (65 percent) and prepreg
(35 percent). Some industry pundits predicted that the use of prepreg would
increase with the quest for automation through automated tape laying (ATL)
machines. However, ATL has been limited to spars so far, and industry experts
like Steve Nolet, TPI Composites’ (Scottsdale, Ariz.) principal
engineer/director of innovation, doubt its ability to match manual placement
rates of 1,500 kg/hr (3,307 lb/hr) and targeted finished product costs of $5/lb
to $10/lb.
INCREASING USE OF
VOLATILE ORGANIC CHEMICALS IN COMPOSITES POSES RISKS TO CONSUMERS FROM
OFF-GASSING
VOCs
(volatile organic compounds) are blamed for damaging the earth's ozone
layer and thereby contributing to global warming. These chemicals are also
dangerous to human health. As a result of these concerns, the last twenty years
have seen a concerted effort by governments to control their release into the
environment.
The
Importance of Control
The
human body reacts to VOCs when breathed in. Some of them cause dermatitis and styrene
is 'reasonably anticipated to be a human carcinogen' according to the US
National Toxicology Program. However,
there is evidence that disputes this. We
believe that there individuals are more sensitive than others and this could explain
the “differences” in the toxicity or carcinogenicity of these compounds.
Most
advanced countries require that any production facility which uses VOC-based
resins in any significant quantity has to have an emission control system as
well as providing clean breathing air and protective suiting, gloves and
goggles for its workers.
Industry
too is striving to minimize the use of these chemicals. Styrene and other
esters can leach out into the atmosphere after the composite has been
manufactured, and this is known as off gassing. Automobile manufacturers have
recognized a condition which they call 'sick car syndrome' and construction
firms too recognize 'sick house syndrome'. Customers don't like these fumes
coming from the products they buy.
Scale
of the Problem
VOCs
make up a significant portion of traditional resin formulations used for
composites. Typically, a lay-up which requires 10 gallons of conventional vinyl
ester resin would put 30 lbs of VOCs into the air. A large bathtub manufacturer
could produce 250,000 tons per year of styrene fumes.
In
the US, since 2006, those firms that produce more than 10 tons of volatile
organic compound (VOC) emissions per year have to meet the Environmental
Protection Agency's Maximum Achievable Control Technology (MACT).
Solutions
There
are a number of solutions to the problem:
Chemistry
- Resins with reduced VOC content. These are known as low-HAP resins (low Hazardous Air Pollutant). Most of these resin formulations offer a range of 32% to 37% styrene content.
- New resins with zero VOC content. So-called green epoxy resins are versatile and are cited as a direct replacement for regular resins even in aerospace applications. These are available as one- and two-part formulations.
Physical
Plant and Process Changes
- VOC abatement equipment requires significant capital investment. Typical solutions involve incineration of fumes. A bathtub manufacturer might incinerate their ¼ million tons of styrene fumes, but for the plant to do that is well beyond the resources of most small and medium sized composite manufacturers.
- Low emission production uses non-atomized spraying for open molding. Closed-mold resin transfer molding and closed die injection for pultrusion provide direct physical constraint of emissions.
Most
smaller manufacturers combine low- or zero-VOC resins with the low emission
production techniques.
Post
Production Emissions
'Bake-out'
is now being used by builders before occupancy of a new building. This
process is designed to drive the VOCs out of the construction materials by
increasing the temperature in the building to as much as 110 deg. F. Outdoor
air exchange is maintained so that hazardous gases are emitted from the
building. In commercial buildings this process is carried out with all
furnishings in place as composites and plastics are heavily used in the
interior. The procedure takes up to two weeks and is obviously performed prior
to occupancy.
At
present there do not appear to be any automobile manufacturers who use
bake-out, though it would seem that it would be something that the component
manufacturers (e.g. composite dashboard assemblies, carpeting and so on) could
carry out.
VOC
Controls - the Future
Unintended
consequences are often a result of legislation, and now some larger
manufacturers who have invested heavily in VOC abatement are finding that their
systems are so efficient that they can use resin formulations with higher VOC
content than they used before. That is certainly not what the legislators
intended.
Demand
is driving researchers to develop 'greener' resins because it is a certainty
that controls will tighten. Resins based on recycled raw materials are now
being marketed.
It
is inevitable that low- and zero-VOC resins will become more widely used as
production volumes increase and raw material prices fall.
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