EPA Air · stack tests by state, industry and year

NAICS 9999: stack tests in California, 2026

• 50Stack 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 2026 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

• 2025 193
• 2024 715
• 2023 322
• 2022 499
• 2021 1,017
• 2020 255
• 2019 290
• 2018 249
• 2017 558

Other industries in California, 2026

• Utilities (NAICS 2211) 327
• Oil and gas extraction (NAICS 2111) 193
• Pipeline transportation (NAICS 4862) 76
• Nonmetallic mineral product manufacturing (NAICS 3272) 60
• Petroleum and coal products manufacturing (NAICS 3241) 48
• Beverage and tobacco manufacturing (NAICS 3121) 45
• Waste management and remediation (NAICS 5622) 31
• Food manufacturing (NAICS 3114) 21
• Justice, public order and safety (NAICS 9221) 20
• Paper manufacturing (NAICS 3222) 12
• Animal production (NAICS 1121) 8
• Food manufacturing (NAICS 3116) 7
• Chemical manufacturing (NAICS 3251) 7
• Food manufacturing (NAICS 3115) 7
• Waste management and remediation (NAICS 5629) 7
• Plastics and rubber products manufacturing (NAICS 3261) 6
• NAICS 4543 6
• Fabricated metal product manufacturing (NAICS 3324) 6
• National security and international affairs (NAICS 9281) 5
• Wood product manufacturing (NAICS 3219) 5
• Food manufacturing (NAICS 3119) 5
• Pipeline transportation (NAICS 4861) 5
• Food manufacturing (NAICS 3118) 4
• Merchant wholesalers, nondurable goods (NAICS 4244) 4
• Mining support (NAICS 2131) 3
• Administration of environmental programs (NAICS 9241) 3

Air-emissions stack tests recorded in California, 2026

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.