There are 194 individual air toxic chemicals and 303 chemicals within 29 groups included in the air toxics emission inventory. This list includes the 188 hazardous air pollutants (HAPs) identified by the EPA, pollutants in the Great Lakes regional air toxics emission inventory project, and pollutants of concern in Minnesota’s outdoor air:

The presentation of emissions data for specific groups of compounds is described below. Efforts are made to avoid the same emission being counted twice. On the MPCA’s website, emissions are reported for various chemical groups while the detailed chemical-specific emissions are available and can be obtained by contacting the MPCA.

Recommendations for reporting data for specific groups of compounds are summarized below in a hierarchy of the most preferred method to the least preferred method. For pollutant groups, only one reporting strategy per group per process should be used. Simultaneous use of more than one reporting strategy (e.g., reporting both individual chromium compounds and total chromium for the same source) will result in double counting.

Metal and cyanide groups

  1. Within a process, and for a given metal or cyanide group, separately report emissions of all individual metal or cyanide compounds [e.g., report emissions of arsenic trioxide (ARSENIC 03, CAS No. 1327-53-3) if the process only has one compound in a metal/cyanide group and it can be reported under that compound]. Do not report it under the group [e.g., arsenic (ARSENIC CAS No. 7440-38-2)]. All individual compounds should be reported as the mass of the total compounds, not just the metal within the compound.
  2. Report just emissions of metal or cyanide within the compound (e.g., if you have emissions of 1 lb. of ARSENIC 03 CAS No. 127-53-3, you can report 0.7574 lb. of ARSENIC, CAS No. 7440-38-2 emissions within the ARSENIC 03 CAS No. 127-53-3).
    • Chromium - Since there is widely varying toxicity, you need to separate chromium compounds into trivalent (CHROMIUM III, CAS No. 16065-83-1) and hexavalent chromium (CHROMIUM VI, CAS No. 18540-29-9) if possible. You may report emissions for CHROMIUM, CAS No. 7440-47-3 if you cannot separate emissions. If the emissions are reported for CHROMIUM, CAS No. 7440-47-3 the emissions will be allocated to CHROMIUM III and CHROMIUM VI based on generic information when the data are used.
    • Do not include metals or cyanide already reported using the more preferred method in number 1. The e-service will give an error message if both are reported.

Dioxins/furans

Report mass emissions of the following 17 individual congeners of chlorinated dibenzodioxins (CDDs) and chlorinated dibenzofurans (CDFs).

Pollutant code Short description CAS No.
HPCDD1234678 1,2,3,4,6,7,8-Heptachlorodibenzodioxin 35822-46-9
HPCDF1234678 1,2,3,4,6,7,8-Heptachlorodibenzofuran 67562-39-4
HPCDF1234789 1,2,3,4,7,8,9-Heptachlorodibenzofuran 55673-89-7
HXCDD,123478 1,2,3,4,7,8-Hexachlorodibenzodioxin 39227-28-6
HXCDD,123678 1,2,3,6,7,8-Hexachlorodibenzodioxin 57653-85-7
HXCDD,123789 1,2,3,7,8,9-Hexachlorodibenzodioxin 19408-74-3
HXCDF,123478 1,2,3,4,7,8-Hexachlorodibenzofuran 70648-26-9
HXCDF,123678 1,2,3,6,7,8-Hexachlorodibenzofuran 57117-44-9
HXCDF,123789 1,2,3,7,8,9-Hexachlorodibenzofuran 72918-21-9
HXCDF,234678 2,3,4,6,7,8-Hexachlorodibenzofuran 60851-34-5
OCDD,TOT Octachlorodibenzodioxins, All Isomers 3268-87-9
OCDF,TOT Octachlordibenzofurans, All Isomers 39001-02-0
PECDD,12378 1,2,3,7,8-Pentachlorodibenzodioxin 40321-76-4
PECDF,12378 1,2,3,7,8-Pentachlordibenzofuran 57117-41-6
PECDF,23478 2,3,4,7,8-Pentachlordibenzofuran 57117-31-4
TCDD,2378 2,3,7,8-Tetrachlorodibenzo-P-Dioxin 1746-01-6
TCDF,2378 2,3,7,8-Tetrachlorodibenzofuran 51207-31-9

Glycol ethers

  1. Report emissions for individual glycol ethers. All individual glycol ethers are shown on the air toxics pollutant list. EPA uses the Toxics Release Inventory (TRI) List of Toxic Chemicals within the Glycol Ethers Category to determine if a chemical falls into a glycol ether category. If the chemical is not listed in Table 1 of the above guidance please use the structural definition provided by EPA to determine if the chemical is a glycol ether. The definition is:
    R - (OCH2CH2)n - OR'  where
    n = 1, 2 or 3
    R = alkyl C7 or less; or R = phenyl or alkyl substituted phenyl;
    R' = H or alkyl C7 or less; or OR' consisting of carboxylic acid ester, sulfate, phosphate, nitrate, or sulfonate.
  2. If you cannot report individual glycol ether emissions, report total emissions of glycol ethers as a group under pollutant code GLYCOL ETHERS. You should not report emissions of one pollutant under both the individual pollutant name and GLYCOL ETHERS. The e-service will give an error message if both are reported.

Xylenes and cresols

  1. Report emissions for individual xylene and cresol isomers. If you report emissions for individual isomers do not report any emissions for total xylenes (XYLENES ISO, CAS No. 1330-20-7) or total cresols (CRESOLS MX IS, CAS No. 1319-77-3) to avoid double counting.
  2. If you cannot report individual emissions of xylenes or cresols, report total emissions of xylenes or cresols as a group under XYLENES ISO, CAS No. 1330-20-7 or CRESOLS MX IS, CAS No. 1319-77-3.

Polycyclic organic matter (POM)

Report emissions of as many individual POM compounds as possible. All POMs are shown on the AT pollutant list.

2023 emissions inventory updates

EPA added 1-bromopropane CAS No. 106-94-5 (also known as 1-BP, n-propyl bromide, and nPB) to the list of Hazardous Air Pollutants (HAPs).

Trichloroethylene (TCE)

In May 2020, the Minnesota Legislature passed a ban on TCE use in the state. The ban was signed into law by the governor and is a first of its kind in the nation. Since the ban was enacted, MPCA has added three additional chemicals to our pollutant reporting list as TCE substitutes.

Pollutant code Short description CAS No.
DCE,12TRANS trans-1,2-DCE 156-60-5
DCE,12MIX 1,2-DCE Compounds/Mixture 540-59-0
BUTOXYPROPA,N 3-butoxypropan-2-ol 5131-66-8

Polyfluoroalkyl substances (PFAS)

MPCA added five PFAS pollutants to the list of reportable pollutants. These pollutants are of particular interest in Minnesota because they have a drinking water health standard.

Pollutant code Short description CAS No.
PFOS Perfluorooctane sulfonic acid 1763-23-1
PFOA Perfluorooctanoic acid 335-67-1
PFBS Perfluorobutanesulfonic acid 375-73-5
PFHxS Perfluorohexanesulfonic acid 355-46-4
PFBA Heptafluorobutyric acid 375-22-4

Aluminum

  1. For the 2020 emission inventory, MPCA added ALUMINUM OXIDE, CAS No. 1344-28-1 and ALUMINUM FL, CAS No. 7784-18-1 to the list of reportable compounds. Report emissions for individual compounds. If you report emissions for individual compounds do not report any emissions for total aluminum to avoid double counting.
  2. If you cannot report individual emissions of aluminum compounds, report total emissions of aluminum under ALUMINUM, CAS No. 7429-90-5.

Vanadium

  1. For the 2020 emission inventory, MPCA added FERROVANADIUM, CAS No. 12604-58-9 to the list of reportable compounds. Report emissions for the individual compound. If you report emissions for ferrovanadium do not report any emissions for total vanadium to avoid double counting.
  2. If you cannot report individual emissions of ferrovanadium, report total emissions of vanadium under VANADIUM, CAS No. 7440-62-2.