Clarification of 

Requirements for 

Inclusion of Continuous 

Emission Monitoring 

Provisions in State 

Implementation Plans . 

MEMORANDUM 

May 9,1980 

FROM: 

Director, Division of Stationary Source 

Enforcement 

TO: 

Enforcement Division Directors, Regions I-X 

Air and Hazardous Materials Division 

Directors, Regions I-X 

During the course of a recent survey of state continuous 

emission monitoring (CEM) regulations for existing stationary 

sources, the following question arose concerning the 

applicability of 40 CFR Part 5 1, Appendix P, which requires 

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Clarification of Requirements for Inclusion of Continuous Emission Monitoring Provisions 

CEM at four categories of existing sources (power plants, 

sulfuric acid plants, nitric acid plants, and fluid bed catalytic 

cracking unit catalyst regenerators at petroleum refineries): 

Appendix P requires CEM at the four listed 

sources if they exceed certain size thresholds 

and, in the case of NOx CEM, power plants and 

nitric acid plants if they are located in areas 

designated nonattainment for nitrogen dioxide. 

If a state, due to the size thresholds, has no 

Appendix P sources, or if a state has no areas 

designated nonattainment for nitrogen dioxide, 

must the state nonetheless promulgate a CEM 

regulation pursuant to 40 CFR 5 1.19(e) in case 

a source exceeding the threshold is 

subsequently constructed in that state or in the 

event an area is later designated nonattainment 

for nitrogen dioxide? 

The question arose because among the reasons some states 

have given for not having complete Appendix P regulations 

are that the sources in those states do not meet the size 

thresholds or that there are no areas in the states designated 

nonattainment for nitrogen dioxide. 

It is our view that a state need not promulgate CEM 

regulations to apply to Appendix P sources not yet in 

existence in the state. Appendix P by its terms permits states, 

in their CEM regulations, to exempt from its coverage sources 

which would be subject to any NSPS requiring CEM. All four 

of the source categories covered by Appendix P would, if 

new, be subject to NSPS continuous monitoring requirements. 

Should a source meeting the Appendix P size threshold be 

subsequently constructed in a state, it would be governed by 

the CEM provisions of the applicable NSPS. Coverage under 

Appendix P would therefore be unnecessary to assuring the 

continuous monitoring of that new source. 

With regard to the absence within a state of areas designated 

nonattainment for nitrogen.dioxide, a state need not require 

NOx monitoring under Appendix P for power plants or nitric 

acid plants where there are currently no nonattainment areas 

for nitrogen dioxide. A reading of Sections 2.1.3 and 2.2 of 

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Clarification of Requirements for Inclusion of Continuous Emission Monitoring Provisions 

Appendix P reveals that the presence of a nonattainment area 

for nitrogen dioxide is so much a part of the description of the 

covered source categories that the absence of such an area 

,would preclude existing power plants and nitric acid plants 

from Appendix P coverage for NOx monitoring. There being 

no covered sources for NOx monitoring, no regulations need 

be enacted to require such monitoring. 

In order, however, to encourage states to assess their CEM 

regulations and to examine those sources covered by them, we 

will suggest to the working group presently involved in further 

developing the Agency's CEM requirements that 40 CFR 

5 1,19(e) a Appendix P be amended similar to 40 CFR 

60.23(b) for NSPS, that it has no existing sources of the type 

covered by the CEM requirements and therefore need not have 

completed Appendix P regulations. A procedure of this sort 

would enable the Agency to better monitor both source and 

state compliance with CEM regulations for existing sources. 

If you have any questions on this matter, please feel free to 

contact Mark Silvermintz (FTS 755-2570) in this Division. 

Edward E. Reich 

cc: 

Richard Rhoads Director. CPDD 

Joseph Sableski, CPDD 

bcc: 

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