Texas Natural Resource Conservation Commission
                      Interoffice Memorandum

To:  New Source Review Permits (NSRP) Technical Staff
Date:  May 18, 1998
From:  Victoria Hsu, P.E., NSRP Division Director
Subject:  Voluntary addition/replacement of control under 116.617, circumvention,
and use of exemptions

1.  Control added or changed voluntarily under Standard Permit 116.617 may not meet current
"best available control technology" standards.  Example: A flare is installed which meets a SIP
requirement, but does not satisfy the conditions of 40 CFR 60.18.  If that is the case, the
representative of the company registering the facility(ies) should be alerted both prior to issuance
of the standard permit and in the language of the permit letter itself that this may cause future
permitting problems.  The prospective impact on possible future SB 1126 changes should also be
stated if the control does not meet "10 Year BACT." 

2.  Voluntary additions of or changes to control under Standard Permit 116.617 are being
claimed in conjunction with exemptions, particularly process changes under 106.261 (old 106)
and 106.262 (old 118) where an exemption condition prohibits change to or addition of control
equipment.  

a.  Example:  A petroleum fuel bulk plant replaces a flare with a regenerative carbon adsorption
unit, prior to increasing throughput (CAS is BACT.).  An exemption claim relying upon the
addition of or change in method of control meeting current BACT will be recognized if the
116.617 registration has been made, our standard permit letter has been issued, and the
exemption claim meets all other applicable requirements.

b.  Example:  A tank currently vented to the atmosphere will be vented to a lean oil absorber (not
BACT), and subsequently see a change of service to a low ESL compound.  116.610(c) and
106.4(b) both prohibit circumvention of the permitting requirements of 116.610, which includes
the requirement for the use of Best Available Control Technology.  Rules 116.617(4), (5) and (7)
place strict limits on what facility additions or changes may be made under this standard permit. 
If a control addition or change is made that does not meet current BACT, and an exemption
claim relying on the addition or change is made immediately after the 116.617 standard permit is
issued, the claim shall be forwarded through your section manager to the division manager for a
circumvention determination.