106c.txt

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                  Texas Air Control Board
            Austin                       Texas
                         Memorandum

To:  Permit Engineers
From:  Lawrence E. Pewitt, P. E., Director, Permits Program
Date:  April 25, 1991
Subject:  Standard Exemption 106 Interpretation

Recently, it has been pointed out that, if the exemption is
interpreted literally, provision (d) completely obviates use
of provision (c).  The logic is that some of the chemicals in
(c) have an L value less than 200 mg/m3 in which case (d)
forbids their use.  Similarly, for the other chemicals in (c)
having no L values or values above 200 mg/m3, provision (d)
allows 1 pound per hour only.  Thus, provision (c) is useless.

The original intent was to have (c) and (d) be independent
requirements.  The point of paragraph (c) was to allow the
exemption of certain compounds even if they would otherwise
not be exemptible under (d).

We will certainly try to resolve this problem in a future
exemption change.  Your input on wording changes would be
appreciated.  In the meantime, please advise exemption
claimants that provision (c) takes precedence over (d) to the
extent of any conflicting statements.

cc:  James C. Myers, P.E., Deputy Director, Regulatory
       Operations
     Debra Barber, Director, Enforcement and Field Operations
       Program