Regulations last checked for updates: Oct 15, 2026

Title 40 - Protection of Environment last revised: Oct 13, 2026
Appendix -
If your boiler or process heater is in this subcategory . . . For the following
pollutants . . .
The emissions must not exceed the following emission limits, except during periods of
startup and shutdown . . .
Using this specified sampling volume or test run duration . . .
1. Units in all subcategories designed to burn solid fuela. HCl0.022 lb per MMBtu of heat inputFor M26A, collect a minimum of 1 dscm per run; for M26 collect a minimum of 120 liters per run.
2. Units in all subcategories designed to burn solid fuel that combust at least 10 percent biomass/bio-based solids on an annual heat input basis and less than 10 percent coal/solid fossil fuels on an annual heat input basisa. Mercury8.0E-07 a lb per MMBtu of heat inputFor M29, collect a minimum of 4 dscm per run; for M30A or M30B, collect a minimum sample as specified in the method; for ASTM D6784 b collect a minimum of 4 dscm.
3. Units in all subcategories designed to burn solid fuel that combust at least 10 percent coal/solid fossil fuels on an annual heat input basis and less than 10 percent biomass/bio-based solids on an annual heat input basisa. Mercury2.0E-06 lb per MMBtu of heat inputFor M29, collect a minimum of 4 dscm per run; for M30A or M30B, collect a minimum sample as specified in the method; for ASTM D6784 b collect a minimum of 4 dscm.
4. Units design to burn coal/solid fossil fuela. Filterable PM (or TSM)1.1E-03 lb per MMBtu of heat input; or (2.3E-05 lb per MMBtu of heat input)Collect a minimum of 3 dscm per run.
5. Pulverized coal boilers designed to burn coal/solid fossil fuela. Carbon monoxide (CO) (or CEMS)130 ppm by volume on a dry basis corrected to 3 percent oxygen, 3-run average; or (320 ppm by volume on a dry basis corrected to 3 percent oxygen, c 30-day rolling average)1 hr minimum sampling time.
6. Stokers designed to burn coal/solid fossil fuela. CO (or CEMS).130 ppm by volume on a dry basis corrected to 3 percent oxygen, 3-run average; or (340 ppm by volume on a dry basis corrected to 3 percent oxygen , c 10-day rolling average)1 hr minimum sampling time.
7. Fluidized bed units designed to burn coal/solid fossil fuela. CO (or CEMS)130 ppm by volume on a dry basis corrected to 3 percent oxygen, 3-run average; or (230 ppm by volume on a dry basis corrected to 3 percent oxygen, c 30-day rolling average)1 hr minimum sampling time.
8. Fluidized bed units with an integrated heat exchanger designed to burn coal/solid fossil fuela. CO (or CEMS)140 ppm by volume on a dry basis corrected to 3 percent oxygen, 3-run average; or (150 ppm by volume on a dry basis corrected to 3 percent oxygen, c 30-day rolling average)1 hr minimum sampling time.
9. Stokers/sloped grate/others designed to burn wet biomass fuela. CO (or CEMS)620 ppm by volume on a dry basis corrected to 3 percent oxygen, 3-run average; or (390 ppm by volume on a dry basis corrected to 3 percent oxygen, c 30-day rolling average)1 hr minimum sampling time.
b. Filterable PM (or TSM)3.0E-02 lb per MMBtu of heat input; or (2.6E-05 lb per MMBtu of heat input)Collect a minimum of 2 dscm per run.
10. Stokers/sloped grate/others designed to burn kiln-dried biomass fuela. CO560 ppm by volume on a dry basis corrected to 3 percent oxygen1 hr minimum sampling time.
b. Filterable PM (or TSM)3.0E-02 lb per MMBtu of heat input; or (4.0E-03 lb per MMBtu of heat input)Collect a minimum of 2 dscm per run
11. Fluidized bed units designed to burn biomass/bio-based solidsa. CO (or CEMS)230 ppm by volume on a dry basis corrected to 3 percent oxygen, 3-run average; or (310 ppm by volume on a dry basis corrected to 3 percent oxygen, c 30-day rolling average)1 hr minimum sampling time.
b. Filterable PM (or TSM)9.8E-03 lb per MMBtu of heat input; or (8.3E-05 a lb per MMBtu of heat input)Collect a minimum of 3 dscm per run
12. Suspension burners designed to burn biomass/bio-based solidsa. CO (or CEMS)2,400 ppm by volume on a dry basis corrected to 3 percent oxygen, 3-run average; or (2,000 ppm by volume on a dry basis corrected to 3 percent oxygen c 10-day rolling average)1 hr minimum sampling time.
b. Filterable PM (or TSM)3.0E-02 lb per MMBtu of heat input; or (6.5E-03 lb per MMBtu of heat input)Collect a minimum of 2 dscm per run.
13. Dutch Ovens/Pile burners designed to burn biomass/bio-based solidsa. CO (or CEMS)1,010 ppm by volume on a dry basis corrected to 3 percent oxygen, 3-run average; or (520 ppm by volume on a dry basis corrected to 3 percent oxygen c 10-day rolling average)1 hr minimum sampling time.
b. Filterable PM (or TSM)8.0E-03 lb per MMBtu of heat input; or (3.9E-05 lb per MMBtu of heat input)Collect a minimum of 3 dscm per run.
14. Fuel cell units designed to burn biomass/bio-based solidsa. CO910 ppm by volume on a dry basis corrected to 3 percent oxygen1 hr minimum sampling time.
b. Filterable PM (or TSM)2.0E-02 lb per MMBtu of heat input; or (2.9E-05 lb per MMBtu of heat input)Collect a minimum of 2 dscm per run.
15. Hybrid suspension grate boiler designed to burn biomass/bio-based solidsa. CO (or CEMS)1,100 ppm by volume on a dry basis corrected to 3 percent oxygen, 3-run average; or (900 ppm by volume on a dry basis corrected to 3 percent oxygen, c 30-day rolling average)1 hr minimum sampling time.
b. Filterable PM (or TSM)2.6E-02 lb per MMBtu of heat input; or (4.4E-04 lb per MMBtu of heat input)Collect a minimum of 3 dscm per run
16. Units designed to burn liquid fuela. HCl4.4E-04 lb per MMBtu of heat inputFor M26A: Collect a minimum of 2 dscm per run; for M26, collect a minimum of 240 liters per run
b. Mercury.4.8E-07 a lb per MMBtu of heat inputFor M29, collect a minimum of 4 dscm per run; for M30A or M30B, collect a minimum sample as specified in the method; for ASTM D6784 b collect a minimum of 4 dscm.
17. Units designed to burn heavy liquid fuela. CO130 ppm by volume on a dry basis corrected to 3 percent oxygen, 3-run average1 hr minimum sampling time.
b. Filterable PM (or TSM)1.3E-02 lb per MMBtu of heat input; or (7.5E-05 lb per MMBtu of heat input)Collect a minimum of 3 dscm per run.
18. Units designed to burn light liquid fuela. CO130 ppm by volume on a dry basis corrected to 3 percent oxygen1 hr minimum sampling time.
b. Filterable PM (or TSM)2.0E-03 a lb per MMBtu of heat input; or (2.9E-05 lb per MMBtu of heat input)Collect a minimum of 3 dscm per run
19. Units designed to burn liquid fuel that are non-continental unitsa. CO130 ppm by volume on a dry basis corrected to 3 percent oxygen, 3-run average based on stack test1 hr minimum sampling time.
b. Filterable PM (or TSM)2.3E-02 lb per MMBtu of heat input; or (8.6E-04 lb per MMBtu of heat input)Collect a minimum of 4 dscm per run
20. Units designed to burn gas 2 (other) gasesa. CO130 ppm by volume on a dry basis corrected to 3 percent oxygen1 hr minimum sampling time.
b. HCl1.7E-03 lb per MMBtu of heat inputFor M26A, Collect a minimum of 2 dscm per run; for M26, collect a minimum of 240 liters per run.
c. Mercury7.9E-06 lb per MMBtu of heat inputFor M29, collect a minimum of 3 dscm per run; for M30A or M30B, collect a minimum sample as specified in the method; for ASTM D6784 b collect a minimum of 3 dscm.
d. Filterable PM (or TSM)6.7E-03 lb per MMBtu of heat input; or (2.1E-04 lb per MMBtu of heat input)Collect a minimum of 3 dscm per run.

a If you are conducting stack tests to demonstrate compliance and your performance tests for this pollutant for at least 2 consecutive years show that your emissions are at or below this limit, you can skip testing according to § 63.7515 if all of the other provision of § 63.7515 are met. For all other pollutants that do not contain a footnote “a”, your performance tests for this pollutant for at least 2 consecutive years must show that your emissions are at or below 75 percent of this limit in order to qualify for skip testing.

b Incorporated by reference, see § 63.14.

c An owner or operator may determine compliance with the carbon monoxide emissions limit using carbon dioxide as a diluent correction in place of oxygen as described in § 63.7525(a)(1). EPA Method 19 F-factors in 40 CFR part 60, appendix A-7, and EPA Method 19 equations in 40 CFR part 60, appendix A-7, must be used to generate the appropriate CO2 correction percentage for the fuel type burned in the unit, and must also take into account that the 3% oxygen correction is to be done on a dry basis. The methodology must account for any CO2 being added to, or removed from, the emissions gas stream as a result of limestone injection, scrubber media, etc. This methodology must be detailed in the site-specific monitoring plan developed according to § 63.7505(d).

[87 FR 60855, Oct. 6, 2022]
authority: 42 U.S.C. 7401
source: 57 FR 61992, Dec. 29, 1992, unless otherwise noted.