1. (1) To satisfy the requirements of R307-306-4(2), the abrasive blasting operation shall use at least one of the following performance standards:

   1. (a) confined blasting;
   2. (b) wet abrasive blasting;
   3. (c) hydroblasting; or
   4. (d) unconfined blasting using abrasives as defined in (2) below.

2. (2) Abrasives.

   1. (a) Abrasives used for dry unconfined blasting referenced in (1) above shall comply with the following performance standards:

      1. (i) Before blasting, the abrasive shall not contain more than 1% by weight material passing a #70 U.S. Standard sieve.
      2. (ii) After blasting the abrasive shall not contain more than 1.8% by weight material 5 microns or smaller.
   2. (b) Abrasives reused for dry unconfined blasting are exempt from (a)(ii) above, but must conform with (a)(i) above.
3. (3) Abrasive Certification. Sources using the performance standard of (1)(d) above to meet the requirements of R307-306-4(2) must demonstrate they have obtained abrasives from a supplier who has certified (submitted test results) to the director at least annually that such abrasives meet the requirements of (2) above.

KEY: air pollution, abrasive blasting, PM10

Date of Last Change: December 15, 2015

Notice of Continuation: October 2, 2024

Authorizing, and Implemented or Interpreted Law: 19-2-101(1)(a)