The Mojave Desert Air Quality Management District (MDAQMD) is proposing significant modifications to Rule 1158 and Rule 1162. Rule 1158 (Electric Power Generating Facilities) is being amended to contain more restrictive NOx emission limits, exemptions, monitoring, recordkeeping, and compliance schedules. All boilers or steam generators will have a NOx RACT emission limit of 30 ppmv for units operating on gaseous fuels and 40 ppmv for units operating on liquid fuels (which is significantly lower than the previous levels of 70 ppmv and 115 ppmv respectively). In addition, combined-cycle turbines have NOx limits based on the efficiency of the turbine rather than a base limit (previously 42 ppmv for gaseous fuels and 65 ppmv for liquid fuels). Units subject to MDAQMD Rule 1157 or 1159 are exempt from Rule 1158 limits. In response to these proposed changes, electric power generating facilities under MDAQMD jurisdiction should review the NOx emissions generated from the stack tests and/or monitoring equipment of the electricity generating units. If these emissions are over the new limit, affected facilities should start researching which add-on controls or operating limits would be necessary to lower their units' NOx emissions to comply with the new limits.

MDAQMD is also proposing to amend Rule 1162 (Polyester Resin Operations) to update the rule's purpose, exemptions, requirements, control device efficiencies, work practices, and records. Fiberglass Boat Manufacturing Operations will be included in Rule 1162. MDAQMD is proposing new control or process requirements for Polyester Resin Operations which include either (1) abiding by new VOC (Volatile Organic Compound) content limits in the resin coating, (2) using a resin with vapor suppressant, (3) using a closed-mold system, or (4) installing a VOC control system. The District is also proposing VOC content limits for the incorporated Fiberglass Boat Manufacturing Operations. Facilities under MDAQMD jurisdiction that performs either of these activities should review this rule to ensure that the resin or gel coatings utilized meet the new VOC content limits. If these limits are not met, affected facilities should start utilizing coatings that do meet the VOC content limits or look into obtaining a VOC control system.

For more information and support about the details and impact of these changes, please contact our office at (949) 567-9880 or visit the District's website.