MODOC COUNTY AIR POLLUTION CONTROL DISTRICT
RULE 8.3 - HEXAVALENT CHROMIUM EMISSIONS FROM CHROME PLATING AND CHROMIC ACID
ANODIZING OPERATIONS
(Amended May 1, 1989)
A. Purpose
To comply with the California Code of Regulations, Section 93102, by controlling airborne emissions of
hexavalent chromium.
B. Definitions
- Ampere-hours : The integral of electrical current applied to a plating tank (amperes) over a period
of time (hours).
- Anti-mist Additive : A chemical which reduces the emission rate from the tank when added to and maintained
in the plating tank.
- Chrome : Metallic chrome.
- Chrome Plating :Either hard or decorative chrome plating.
- Chromic Acid : An aqueous solution of chromium trioxide (CrO3), or commercial solution containing chromic
acid, dichromic acid (H2CrO7), or trichromic acid (H2Cr3O10).
- Chromic Acid Anodizing :The electrolytic process by which a metal surface is converted to an oxide surface
coating in a solution containing chromic acid.
- Chromium : Hexavalent chromium.
- Control Equipment : Any device which reduces emissions from the emissions collection system.
- Decorative Chrome Plating : The process by which chromium is electrodeposited from a solution containing
compounds of chromium onto an object resulting in a chrome layer 1 micron (0.04 mil) thick or less.
- Emission Factor : The mass of chromium emitted during a test conducted in the emissions collection system
in accordance with ARB Test Method 425, divided by the ampere-hours consumed by the tanks in the tested emissions
collection system, expressed as the mass of chromium emitted per ampere-hour of electrical current consumed.
- Emissions Collection System : A device or apparatus used to gather chromium emissions from the surface
of a chrome plating or chromic acid anodizing tank or tanks.
- Facility : A business or businesses engaged in chrome plating or chromic acid anodizing which are owned
or operated by the same person or persons and are located on the same parcel or on contiguous parcels.
- Facilitywide Emissions from Hard Chrome Plating or Chromic Acid Anodizing : The total emissions
from all hard chrome plating or chromic acid anodizing at the facility over a calendar year. Emissions shall be
calculated as the sum of emissions from the emissions collection system at the facility. The emissions from an
emissions collection system shall be calculated by multiplying the emission factor for that emissions collection
system by the sum of ampere-hours consumed during that year for all of the tanks served by the emissions collection
system.
- Hard Chrome Plating : The process by which chromium is electrodeposited from a solution containing compounds
of chromium onto an object resulting in a chrome layer thicker than 1 micron (0.04 mil).
- Plating Tank : Any container used to hold a chromium or chromic acid solution for the purposes of chrome
plating or chromic acid anodizing.
- Uncontrolled Chromium Emissions from the Hard Chrome Plating or Chromic Acid Anodizing Facility
: The chromium emissions from the emissions collection systems at the facility calculated as if no control equipment
is in use. For the purpose of determining compliance with this rule, the uncontrolled chromium emissions shall
be calculated using an emission factor based on tests conducted in accordance with ARB Test Method 425 or 14 mg/ampere-hour,
whichever is less.
C. Requirements for Decorative Chrome Plating Facilities
- No person shall operate a decorative chrome plating tank unless an anti-mist additive is continuously maintained
in the plating tank, or control equipment is installed and used, in a manner which has been demonstrated to and
approved by the Control Officer as reducing chromium emissions by 95 percent or more relative to chromium emissions
when an anti-mist additive is not maintained, or control equipment is not installed and used.
D. Requirements for Hard Chrome Plating and Chromic Acid Anodizing Facilities
- The owners or operators of all hard chrome plating and chromic acid anodizing facilities shall maintain a continuous
record of current integrated over time (ampere-hours) for all plating tanks for each collection system used in
the hard chrome plating or chromic acid anodizing operations and shall submit the information to the Control Officer.
- No person shall operate a plating tank for hard chrome plating or chromic acid anodizing unless the tank has
an emissions collection system.
- No person shall operate a hard chrome plating or chromic acid anodizing tank unless:
- the chromium emissions from the emissions collection system serving the plating tank have been reduced by 95
percent or more of the uncontrolled chromium emissions or
- the chromium emissions from the emissions collection system serving the plating tank have been reduced to less
than 0.15 milligrams (mg) of chromium per ampere-hour of electrical charge applied to the plating tank.
- No person shall operate a hard chrome plating tank or chromic acid anodizing tank at a facility if facilitywide
chromium emissions from hard chrome plating or chromic acid anodizing are greater than 2 pounds per year, but less
than 10 pounds per year, unless:
- the chromium emissions from the emissions collection systems serving the plating tanks have been reduced by
at least 99 percent of the uncontrolled chromium emissions from the hard chrome plating or chromic acid anodizing
facility or
- the chromium emissions from the emissions collection systems are reduced to less than 0.03 mg of chromium per
ampere-hour of electrical charge applied to the tanks.
- No person shall operate a hard chrome plating or chromic acid anodizing tank at a facility if facilitywide
chromium emissions from hard chrome plating or chromic acid anodizing are 10 pounds per year or greater unless:
- the chromium emissions from the emissions collection systems serving the plating tanks have been reduced by
at least 99.8 percent of the uncontrolled chromium emissions from the hard chrome plating or chromic acid anodizing
facility or
- the chromium emissions from the emissions collection systems are reduced to less than 0.006 mg of chromium
per ampere-hour electrical charge applied to the tanks.
E. Compliance Schedule
The owner or operator of any facility subject to this rule shall comply with its provisions at the time the
facility begins operation.