
From the U.S. Code Online via GPO Access
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[Laws in effect as of January 23, 2000]
[Document not affected by Public Laws enacted between
  January 23, 2000 and December 4, 2001]
[CITE: 42USC7423]

 
                 TITLE 42--THE PUBLIC HEALTH AND WELFARE
 
            CHAPTER 85--AIR POLLUTION PREVENTION AND CONTROL
 
                  SUBCHAPTER I--PROGRAMS AND ACTIVITIES
 
              Part A--Air Quality and Emission Limitations
 
Sec. 7423. Stack heights


(a) Heights in excess of good engineering practice; other dispersion 
        techniques

    The degree of emission limitation required for control of any air 
pollutant under an applicable implementation plan under this subchapter 
shall not be affected in any manner by--
        (1) so much of the stack height of any source as exceeds good 
    engineering practice (as determined under regulations promulgated by 
    the Administrator), or
        (2) any other dispersion technique.

The preceding sentence shall not apply with respect to stack heights in 
existence before December 31, 1970, or dispersion techniques implemented 
before such date. In establishing an emission limitation for coal-fired 
steam electric generating units which are subject to the provisions of 
section 7418 of this title and which commenced operation before July 1, 
1957, the effect of the entire stack height of stacks for which a 
construction contract was awarded before February 8, 1974, may be taken 
into account.

(b) Dispersion technique

    For the purpose of this section, the term ``dispersion technique'' 
includes any intermittent or supplemental control of air pollutants 
varying with atmospheric conditions.

(c) Regulations; good engineering practice

    Not later than six months after August 7, 1977, the Administrator, 
shall after notice and opportunity for public hearing, promulgate 
regulations to carry out this section. For purposes of this section, 
good engineering practice means, with respect to stack heights, the 
height necessary to insure that emissions from the stack do not result 
in excessive concentrations of any air pollutant in the immediate 
vicinity of the source as a result of atmospheric downwash, eddies and 
wakes which may be created by the source itself, nearby structures or 
nearby terrain obstacles (as determined by the Administrator). For 
purposes of this section such height shall not exceed two and a half 
times the height of such source unless the owner or operator of the 
source demonstrates, after notice and opportunity for public hearing, to 
the satisfaction of the Administrator, that a greater height is 
necessary as provided under the preceding sentence. In no event may the 
Administrator prohibit any increase in any stack height or restrict in 
any manner the stack height of any source.

(July 14, 1955, ch. 360, title I, Sec. 123, as added Pub. L. 95-95, 
title I, Sec. 121, Aug. 7, 1977, 91 Stat. 721.)


                             Effective Date

    Section effective Aug. 7, 1977, except as otherwise expressly 
provided, see section 406(d) of Pub. L. 95-95, set out as an Effective 
Date of 1977 Amendment note under section 7401 of this title.
