Several changes in bulk tank SCC (BTSCC) regulations were proposed at the 1998 annual meeting of the National Conference of Interstate Milk Shippers (NCIMS) by the National Mastitis Council and other proponents. Proposals included 1) using a geometric mean BTSCC in place of the arithmetic mean, reducing the current limit for BTSCC from 750,000 to 400,000, and modifying current regulatory protocols. The purpose of this research was to evaluate possible impacts of proposed changes upon producers in warm climates. Data were monthly BTSCC values, provided by state regulatory agencies in West Texas, Louisiana, and Mississippi. Fifty producers from each state were selected by lot, and all 1998 monthly records were included (n = 1602). Computer simulation was used to compare regulatory actions that would have resulted under current and proposed regulations. Possible regulatory actions were 1) notification of noncompliance and 2) suspension of permits to sell milk. At the 750,000 BTSCC limit, both programs resulted in 41 regulatory actions, but the proposed program had a higher rate of suspensions to notices. A twofold increase in regulatory actions per 100,000 incremental decrease in BTSCC limit below 750,000 resulted under both programs. Actual results could be lower due to the assumption that no management adjustments were made by producers in response to changes in regulations. However, the magnitude of increased actions against producers indicated that lowering limits quickly could be disruptive if producers failed to adjust management quickly and effectively to comply with lower limits.