SISAPCD RULE 8.4 HEX. CHROM. AIRBORNE TOXIC CONTROL MEASURE          
LAST REVISED 07/20/91          
          
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          Rule 8.4 Hexavalent Chromium Airborne Toxic Control Measure
                   Cooling Towers
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          A. Purpose
             To  comply  with  the  California Code of Regulations, Section
             93102.   This  airborne  toxic  control  measure  will  reduce
             hexavalent chromium emissions  from  chromatic treated cooling
             towers  and  cancer incidence to the lowest  level  achievable
             through application  of  best  available control technology at
             operations subject to this measure.

          B. Definitions
             For purposes of this section, the  following definitions shall
             apply:

             1.Cooling Tower
                Any  open  water  recirculation  device   which  evaporates
                circulating water to remove heat from a process,  building,
                or refrigeration device, and puts the heat into the ambient
                air.

            2. Hexavalent Chromium
                A  cancer-causing  substance  existing  as  part of various
                inorganic   chromate   compounds,   for   example,   sodium
                dichromate or lead chromate.

            3. Water Treatment Chemicals
                Any  combination  of chemicals added to cooling tower water
                including  tracers,   corrosion  inhibitors,  antiscalants,
                dispersants, biocides.

          C. Requirements
            1.  Hexavalent Chromium Removal
                Effective  September 12,  1990  no  person  shall  add  any
                hexavalent chromium  containing  chemicals  or any compound
                that  may  produce  hexavalent chromium to a cooling  tower
                operating in the District.

            2.  Circulating Water Concentration - Wooden Cooling Towers
                Effective September 12,  1990,  no  person  shall operate a
                wooden  cooling tower in the District unless the  following
                requirements are met:
               a.  From September  12,  1990  to March 12, 1991, hexavalent
                   chromium  levels in the circulating  water  are  not  to
                   exceed 8 milligrams/liter of circulating water.
               b.  After March  12, 1991, hexavalent chromium levels in the
                   circulating   water    are    not    to    exceed   0.15
                   milligrams/liter of circulating water.
                c. A decrease in hexavalent concentrate in the  circulating
                   water must be demonstrated each month during a period of
                   up to six months following the compliance date  in order
                   to  avoid  being  cited  for  a  violation  of  the 0.15
                   milligrams/liter limit.

             3. Circulating Water Concentration - Non-Wooden Cooling
                Effective  September  12,  1990, no person shall operate  a
                non-wooden  cooling tower unless  the  hexavalent  chromium
                levels do not  exceed  0.15 milligrams/liter of circulating
                water.

          D. Reporting
             1. By December 12, 1990 any  owner/operator of a cooling tower
                shall notify the District in  writing regarding the follow-
                ing   information   about   the   cooling    tower.     Any
                owner/operator  of  a newly constructed cooling tower shall
                provide the District  with  the  following  information  at
                least 90 days before the tower is operated:
                a. Owner/operator of the tower
               b.  Location of the tower
               c. Cooling tower type and material of construction
               d.  Whether  hexavalent  chromium  based treatment chemicals
                   were previously used in the cooling tower
               e.  If hexavalent chromium based chemicals  were  previously
                   used, when they were discontinued
               f.  A description of the alternate treatment program chosen,
                   as well as the circulating water monitoring plan.

          E. Monitoring - General:
            1.  Effective  September  12,  1990, any person subject to  the
                requirements of B.2. or B.3.  shall  test  the  circulating
                water in the cooling tower at least once every six calendar
                months   to   determine  the  concentration  of  hexavalent
                chromium.  Testing may be discontinued when two consecutive
                required tests show hexavalent chromium concentrations less
                than  0.15  milligrams/liter  of  circulating  water.   The
                District may  require  testing  of the circulating water at
                any time if the District has reason  to  believe  the water
                may contain hexavalent chromium.

            2.  Any  person subject to the monitoring requirements in  D.1.
                above  or  E.1. below shall maintain records of the results
                of all required  tests  of  circulating water for two years
                and provide them to the District upon request.

             3. Monitoring requirements may be  waived  by the District for
                any owner/operator of a cooling tower who  demonstrates  to
                the  District  that the hexavalent chromium based treatment
                chemical has never  been  used  in the cooling tower or has
                not been utilized for a period of  at  least one year prior
                to the appropriate compliance date.

          F. Monitoring - Wooden Cooling Towers
            1.  Any person subject to the requirements of B.2.b. shall test
                the circulating water at least once every calendar month to
                determine the concentration of hexavalent chromium.

          G. Determination of Hexavalent Chromium Content
            1.  Samples   of  circulating  water  shall  be  analyzed   for
                hexavalent  chromium  using American Public Health Associa-
                tion Method 312 B or an  equivalent  method approved by the
                District.

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