EPA Air · stack tests by state, industry and year

NAICS 9999: stack tests in California, 2025

• 193Stack tests

A stack test measures what a source actually emits, at the stack, against the limit in its permit. Each row is one stack test recorded during 2025 at a California source whose primary industry code is NAICS 9999. A facility filing more than one industry code is counted under the first one on its record.

NAICS 9999 in California, other years

• 2026 50
• 2024 715
• 2023 322
• 2022 499
• 2021 1,017
• 2020 255
• 2019 290
• 2018 249
• 2017 558

Other industries in California, 2025

• Utilities (NAICS 2211) 2,709
• Oil and gas extraction (NAICS 2111) 1,287
• Petroleum and coal products manufacturing (NAICS 3241) 177
• Food manufacturing (NAICS 3114) 146
• Food manufacturing (NAICS 3115) 111
• Nonmetallic mineral product manufacturing (NAICS 3279) 100
• Beverage and tobacco manufacturing (NAICS 3121) 94
• Waste management and remediation (NAICS 5622) 74
• Nonmetallic mineral product manufacturing (NAICS 3272) 67
• Utilities (NAICS 2213) 63
• Animal production (NAICS 1121) 52
• Merchant wholesalers, nondurable goods (NAICS 4247) 45
• Fabricated metal product manufacturing (NAICS 3324) 31
• Pipeline transportation (NAICS 4862) 31
• Justice, public order and safety (NAICS 9221) 20
• Mining and quarrying (NAICS 2123) 18
• Plastics and rubber products manufacturing (NAICS 3261) 16
• Food manufacturing (NAICS 3119) 12
• Waste management and remediation (NAICS 5629) 12
• Food manufacturing (NAICS 3111) 10
• Food manufacturing (NAICS 3116) 9
• Chemical manufacturing (NAICS 3252) 8
• Nonmetallic mineral product manufacturing (NAICS 3273) 8
• Fabricated metal product manufacturing (NAICS 3328) 6
• Crop production (NAICS 1113) 6
• NAICS 4523 6
• National security and international affairs (NAICS 9281) 6
• Personal and laundry services (NAICS 8129) 5
• Furniture and related product manufacturing (NAICS 3379) 5
• Pipeline transportation (NAICS 4861) 4
• Electrical equipment and appliance manufacturing (NAICS 3351) 4
• Food manufacturing (NAICS 3118) 4
• Primary metal manufacturing (NAICS 3314) 4
• Paper manufacturing (NAICS 3222) 3
• Food manufacturing (NAICS 3112) 3
• Mining and quarrying (NAICS 2122) 3
• Hospitals (NAICS 6221) 3
• Chemical manufacturing (NAICS 3251) 3
• Administrative and support services (NAICS 5617) 3

Air-emissions stack tests recorded in California, 2025

Primary NAICS code as filed on the facility record; dates as filed by the agency that recorded the stack test. Figures from EPA’s ICIS-AIR download.