N.M. Code R. § 20.2.19.111
Compliance with 20.2.19.109 NMAC shall be determined consistent with the method for manual stack testing set forth by the US EPA at 40 CFR, Part 60, Appendix A, Methods 1 through 5, or any other method receiving prior approval from the Department. Upon request of the Department, the owner or operator of potash, salt or sodium sulfate processing equipment shall perform stack testing according to the method stated above and report the results of such tests in the format and time period specified by the Department. The Department shall not require testing of a stack or stacks more frequently than annually unless the Department has reason to believe that the emissions from the stack or stacks may be in violation of applicable emission limits, or a test is necessary to demonstrate compliance after the completion of measures intended to gain compliance on a stack or stacks previously determined to be in violation of applicable emission limits. The owner or operator shall inform the Department of the dates and times of such testing so that the Department may have the opportunity to have an observer present during testing.
N.M. Code R. § 20.2.19.111