(Adopted: March 16, 1981)

                                       Rule 476
                              Steam Generating Equipment

          (a)  A  person  shall  not discharge into the atmosphere from any
               equipment having a maximum heat input rate of more than 12.5
               million kilogram calories  (50 million BTU) per hour used to
               produce steam, for which a permit  to  build, erect, install
               or  expand is required after May 7, 1976,  air  contaminants
               that exceed the following:

               (1)  Oxides  of  nitrogen,  expressed  as  nitrogen  dioxide
                    (NO2), calculated at 3 percent of oxygen on a dry basis
                    averaged over a minimum of 15 minutes, as shown in  the
                    following table:

          FUEL                   GAS                   LIQUID OR SOLID
          CONCENTRATION        25 ppm NO                 225 ppm NO

               (2)  Combustion  contaminants   that   exceed  both  of  the
                    following two limits:

                    (A)  5 kilograms (11 pounds) per hour.

                    (B)  23  milligrams  per  cubic  meter   (0.01  gr/SCF)
                         calculated  at  3  percent  oxygen on a dry  basis
                         averaged over a minimum of 15 consecutive minutes.

          (b)  Nothing in this rule shall be construed  as  preventing  the
               maintenance  or preventing the alteration or modification of
               existing steam  generating equipment which will not increase
               the mass rate of air contaminant emissions.