The San Joaquin Valley Unified Air Pollution Control District has amended Rule 4570 to broaden the rule’s scope in regulating air emissions from confined animal feeding operations (CAFOs). Under the revised rule, enacted October 21, 2010, after a public hearing, the regulatory threshold for dairies dropped from 1,000 head of milking cows to 500 head, and the threshold for chicken and duck ranches dropped from 650,000 head to 400,000 head. The amended rule also applies to beef feedlots, other cattle operations and hog farms.

The amended rule offers a menu of mitigation measures, including best manure management practices for manure that regulated facilities can use depending on type and location. According to the district, the amendments are expected to cut volatile organic compound emissions from CAFOs by more than 31 tons per day.