United States
Environmental Protection
Agency
Region 5
77 West Jackson Boulevard
Chicago, Illinois 60604
EPA 905-F-00-027
October 2000
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Chromium compounds
are considered highly
toxic to humans.
Chromium (VT), or
hexachrome, can cause
ulcers of the skin,
irritation of the nasal
mucosa, and irritation of
the gastrointestinal tract,
and adverse effects in the
kidneys and liver.
Based on animal and
human studies,
chromium (VT) and its
compounds should be
considered probable
carcinogens in humans
exposed by inhalation.
TECHNICAL FACT
SHEET FOR CHROMIUM
HAZARDS AND
ALTERNATIVES
EPA PARTNERSHIP AND YOU...
The United States Environmental Protection Agency (EPA) has identified
numerous persistent, bioaccumulative and/or toxic chemicals that may be
present in some industrial hazardous wastes regulated under the Resource
Conservation and Recovery Act (RCRA). In addition to its ongoing
regulatory activities, EPA will encourage efforts to achieve reduction of the generation of
chemicals that are either persistent, bioaccumulative and/or toxic. EPA will also work with
states, industry, and environmental groups through workshops, technical assistance programs,
partnership agreements, regulatory reinvention projects, and other strategies to promote progress
toward the goal of reducing the generation of RCRA PBT's in hazardous waste by 50 percent
by the year 2005.
THE CHROMIUM CONNECTION
Chromium (III) occurs naturally in the environment. Chromium (VT)
is generally produced by industrial processes, and used in such
industries as pigment manufacturing, leather tanning, wood treatment
and chrome plating. The primary use for chromium compounds containing chromium
(VT) is in the metal finishing industry for both decorative and functional purposes.
Chromium is oftenchosen as a surface finish because it possesses a low coefficient of
friction, high hardness, good corrosion resistance, high heat resistance and anti-galling
properties. Due to its toxicity and suspected carcinogenicity, however, chromium is
heavily regulated for the protection of human health and of the environment. These
regulatory requirements, as well as the growing awareness among metal platers
regarding the health effects of chromium exposure, have led to a search for acceptable
alternatives to using chromium in the electroplating industry.
Here are some of the uses for chromium:
X Corrosion resistance for metals
X Gives metals longer wear
X Electrical insulation of metals
X Decorative purposes (for metals)
X As chromium sulfate, used to stabilize collagen in hides when tanning leather
X A component of pigments used in the printing industry
X A component of paint used in industrial applications
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Here are some of the industries that may use chromium:
X Automotive manufacturing/repair
X Aerospace industry
X Leather tanneries
X Metal finishers
X Pigment manufacturing
X Printing
X Painting
X Wood treatment
BREAKING THE TIE WITH CHROMIUM
There is no known single replacement for chromium in
electroplating and other process,
however, there are some alternative
technologies available that can
replace electroplating in specific
applications. Testing should be done on a site-specific
basis to determine the most feasible coating alternative. In
many cases, alternative surface finishes prove to be cost-
effective and environmentally beneficial replacements for
chromium.
Here are several chromium alternatives:
Electroless Plating - Electroless plating is a process in
which metal ions in a dilute aqueous solution are deposited
onto a substrate by means of a continuous reaction. Many
metals and alloys can be deposited onto substrates by
electroless plating, but nickel is the most common
replacement for chromium. Nickel coatings have excellent
wear and corrosion resistance, and may be used in a wide
range of applications. However, risks from hazardous
vapor and corrosive chemicals still exist in this process.
Chemical Vapor Deposition (CVD) - Chemical vapor
deposition, or CVD, is a process in which a coating is
deposited onto a substrate by a reactive vapor that is
typically a metal halide, metal carbonyl, hydride, or
organometallic compound. CVD provides a thick, dense,
high-purity film on substrates. Due to the high
temperatures necessary to complete this process,
temperature-sensitive substrates cannot be coated with
CVD.
Surface Hardening - Surface hardening is a process in
which a steel substrate is heated to the lowest temperature
at which a gaseous medium (typically carbon or nitrogen)
will absorb and diffuse into the surface. Substrates that are
subjected to surface hardening demonstrate good wear
resistance; however, use of this process is also limited to
heat-resistant substrates. Some of the spent baths used
after coating may be considered to be hazardous waste.
Thermal Spraying - Thermal spraying is a particle impact
method in which a coating material is melted and then
projected toward a substrate with compressed air or gas.
Thermal spraying offers corrosion and wear resistance, but
cannot effectively coat complex substrates. This process
also generates dust and fumes that may be health hazards.
Physical Vapor Deposition/Vacuum Coating - Vacuum
coating uses positive ions or neutral atoms to bombard a
substrate with coating material. This technology is
environmentally benign, very versatile, and offers
improved adhesion and film structure. The downside of
vacuum coating is its high capital cost, high voltage
requirements, and use of toxic chemicals.
Other Chromium Plating Alternatives - Other metal
finishing technologies include the use of sulfuric acid
anodizing, In-Mold Plating, the application of zirconium
oxide coating or applying other composites or alloys as
surface treatments. One of these alternative finishing
technologies may be a viable chromium plating alternative
depending on the composition and the functional
requirements of the parts that are to be treated.
In the Wood Treatment Industries - Several alternatives
exist in the wood preservation industry which replace
chromium-based products. Boron-based sprays, dusts or
pastes can be applied to the wood's surface to help in
reducing decay. Another option for protecting wood
without using chromium is by inserting boron-treated rods
directly into the body of the wood.
These rods will dissolve and will
then diffuse throughout the wood as
the moisture content increases, thus
treating and protecting the wood.
In the Printing and Painting Industries - Waste paint and
printing inks sometimes contain chromium. In addition,
when specific types of aerosol paints are applied, small
amounts of chromium in the paint can be released into the
air and inhaled. Alternative coatings, such as electrostatic
or powder coatings, in addition to the use of chromium-
free paints should be considered and tests performed on a
site-specific basis to determine the most feasible coating
alternative.
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In addition, process modifications can reduce chromium
waste generation and allow for the recycling of chromium
within various industrial processes. Though these methods
are commonly associated with metal finishing, similar
methods can be implemented in a wide variety of
industries with similar results. Process modifications in
addition to chromium alternatives can reduce waste
disposal and input material costs while lessening
environmental impacts and creating a positive business
image.
Here are several examples of chromium process
modifications:
Dragout Recovery and Reduction - Dragout recovery and
reduction can be accomplished in many ways. Reducing
surface area and using designs which promote rapid
drainage from plating racks can lead to reduced dragout
volumes by maximizing drainage directly into process
tanks. In a similar fashion, dragout drain boards and drip
tanks allow plating solutions to be returned directly to the
process tanks. Implementing revised rinsing techniques
and technologies which reduce rinse volumes and limit the
introduction of impurities can allow rinse solutions to be
returned to the plating process. The added water present
in the rinse solution can compensate for evaporative losses.
Evaporation - Evaporation is a commonly used method
for the recovery of metal salts used in the metal finishing
industry. This process concentrates the plating chemicals
through evaporation of plating solutions. The resulting
concentrated solution can then be reintroduced into the
process tanks and reduce the need for the addition of new
raw materials. In addition, some
evaporative recovery systems contain
systems which condense the water vapor
removed from the plating solution. The
resulting water can then be reintroduced
into process tanks, further reducing costs.
Reverse Osmosis - Reverse osmosis systems are similar to
evaporative systems since they can recover both plating
solutions and water. Reverse osmosis relies on a
membrane through which water can pass, but plating
chemicals cannot. By circulating plating solutions through
this membrane, plating chemicals and water are separated.
The resulting concentrated plating solution can then be
returned to the process tanks and the resulting water can be
reintroduced into the system as rinse and make-up water.
Other Technologies - Other technologies or management
practices such as the application of fluorosurfactant fume
suppressant, using tank chemistry monitors, and using
written procedures for bath make-up and additions may
reduce chromium waste generation.
MEASURE YOUR SUCCESS
There are many companies that have
implemented successful chromium
alternatives and chromium reduction
plans in their process operations. Many
companies have also benefitted from
savings in reducing chromium use and replacing chromium
with the more environmentally friendly alternatives. Here
are some success stories for several types of chromium
reduction and replacement alternatives:
• A plating plant in Ohio reduced its annual chromium
use from 700 pounds to 400 pounds while also
maintaining identical production. The plant
accomplished this chromium reduction by installing a
closed-loop electropolish process that pipes rinse water
through a heavy metal exchange cylinder and reuses it
in the process. They also converted a stave rinse to a
spray rinse, saving 200 pounds of chrome per year.
• A tannery was found to have the potential to reduce
chromium wastes by utilizing the following
techniques; recycle used chromium effluent (savings of
$5,000/yr); precipitate chromium wastes with
hydroxide, settle, and re-dissolve with acid and reuse,
reducing chromium in the wastewater and saving
$l,000/yr. The implementation of these techniques
could reduce chromium purchases by 2 metric tons per
year.
• A company replaced its chrome bright-dipping process
(used on brass kitchen fixtures) with a hydrogen
peroxide-based process. This change resulted in a
reduction in the quantity of chromium waste and a
reduction in the consumption of materials used to treat
chromium wastes. There was no significant cost
associated with the replacement of chromium, and
resulted in a savings of approximately $6,000 per year.
• Another plating company reconfigured their rinse
tanks using some of the process modifications
previously mentioned and decreased water flow rates
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which initially reduced their wastewater discharge by
50 percent. In addition, inexpensive flow restrictors
were installed to reduce the flow of water into rinse
tanks. This modification further reduced daily
wastewater discharges from 40,000 gallons to 11,000
gallons. Not only did this modification have a positive
impact on the environment, but is saved the company
over $18,000 annually. These modifications in
addition to other waste volume reduction techniques
have resulted in an total annual savings of nearly
$24,000 while maintaining production rates and
quality standards.
• An extremely inexpensive ($500) and easily
accomplished process modification involving the
redesign of a parts plating basket resulted in a dragout
reduction of approximately 55 percent, reduced
wastewater discharge concentrations, and reduced raw
material costs by $250 per year. While not as complex
or dramatic as other process modifications, simple
waste reduction steps can have significant positive
effects on the environment and the bottom line.
FOR MORE INFORMATION...
There are various resources to locate more information on
chromium reduction and alternatives for your workplace.
Here a just a few of the websites available via the Internet
and government agencies listings that would be able to
provide more information.
Websites
Government Listings
U.S. EPA Region 5
P2 Hotline
=§> 888/745-7272 (888-PIK-P2P2)
Illinois Environmental Protection Agency
Office of Pollution Prevention
^> 217/782-8700
Indiana Dept. of Environmental Mgmt.
Office of Pollution Prevention
=£> 317/232-8172
Michigan Dept. of Environmental Quality
Environmental Assistance Division
^>800/662-9278
Minnesota Technical Assistance Program
^> 612/624-1300
Ohio Environmental Protection Agency
Office of Pollution Prevention
^> 614/644-3469
Wisconsin Dept. of Natural Resources
Cooperative Environmental Assistance
=§> 608/267-9700
www.epa.gov/reg5rcra/wptdiv/
p2pages/index. html
www.manufacturing.net/magazine
buzz.ea.ucla.edu/cct.froines.news.html
www.sni.net/light/p3/cdphe_05.htm
www.turi.ort/P2GEMS
www.emcentre.com
www.mntap.umn.edu
metalfinishing-sc.com
www.epa.ohio.gov/opp
es.epa.gov/studies (EnviroSense)
www.pprc.org/pprc
www.deq.state.mi.us/ead/p2sect/
www.epa.gov/opptintr/p2home
www.surfacefinishing.com
www.pwrc.usgs. gov/new/chrback.htm
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