What is Tier II?
In 1986, the Emergency Planning and Community Right-to-Know Act (EPCRA) was passed due to rising environmental and safety concerns regarding the storage of toxic chemicals. Section 312, or Tier II, was included in this bill, which required applicable facilities to report hazardous and toxic substances stored onsite. The first submission deadline was March 1, 1988, with annual reports due on March 1 for each subsequent year. The report must be submitted in accordance with state-specific requirements. States typically require electronic filing through an online Tier II portal, either EPA’s Tier2 Submit software or comparable systems such as E-Plan.
Facilities must report any hazardous chemical or mixture stored onsite containing greater than or equal to 10,000 pounds unless otherwise exempted. The threshold may be lower for chemicals containing an Extremely Hazardous Substance (EHS) per 40 CFR 355. For example, if the total quantity of sulfuric acid (a listed EHS chemical) is greater than or equal to 500 pounds, all substances with sulfuric acid in the composition must be included in the report, unless otherwise exempted. The full list of EHS chemicals is available in EPA’s List of Lists, under the column “EPCRA 302 EHS TPQ.” Keep in mind that the Threshold Planning Quantity (TPQ) shown there applies to Emergency Planning Notification (EPCRA Section 302) and does not necessarily match the Tier II reporting threshold.
Facilities that trigger Tier II Chemical Inventory Reporting must submit key facility information to support emergency response planning. This includes, at a minimum, the average and maximum onsite quantities, storage locations, and the hazards associated with each reported chemical. As of June 13, 2016, there are thirteen (13) physical hazards and eleven (11) health hazards. Chemicals with properties of flammability and carcinogenicity are examples of physical and health hazards, respectively.
Revisions to EPCRA
On Monday, November 17, 2025, EPA released a final rule (90 FR 51187) to make several updates to EPCRA Tier II hazardous chemical inventory reporting requirements. This final rule is effective on January 16, 2026, with the first Tier 2 report due on March 1, 2027, utilizing the updated hazard categories.
EPA has added several administrative changes to 40 CFR 370. For example, each letter of the term “Extremely Hazardous Substance” will be capitalized. EPA will also be removing historical compliance dates and historic clarification for electronic reporting from 40 CFR 370.33 and 40 CFR 370.45. Throughout the regulation, EPA’s use of Material Safety Data Sheet (MSDS) will now be replaced with Safety Data Sheet (SDS) to better align with Occupational Safety and Health Administration (OSHA) regulations.
To ensure consistency throughout the regulations, EPA is moving definitions from 40 CFR 370.66 to 40 CFR 370.3. 40 CFR 370.66 will now be titled [Reserved] with a note and reference to the new location as a result of this change. Additionally, the definition for “hazard category” will be amended to be consistent with OSHA.
Hazard category means the classification of a chemical’s hazard(s) into classes with their categories as are reported in Section 2 of SDSs in accordance with 29 CFR 1910.1200. Hazard categories are divided by hazard class into health and physical hazards:
(1) Health hazard means a chemical that is classified into one of the following hazard classes: acute toxicity (oral, dermal, or inhalation); aspiration hazard; carcinogenicity; germ cell mutagenicity; reproductive toxicity; respiratory sensitizer; skin sensitizer; serious eye damage/eye irritation; simple asphyxiant; skin corrosion or irritation; specific target organ toxicity (single exposure) or (repeated or prolonged exposure); and hazard not otherwise classified.
(2) Physical hazard means a chemical that is classified into one of the following hazard classes: aerosols; chemicals under pressure; combustible dust; corrosive to metal; desensitized explosive; explosives; flammable (gases, liquids, or solids); gas under pressure; in contact with water emits flammable gases; organic peroxides; oxidizing (gases, liquids, or solids); pyrophoric (liquids or solids); self-heating chemicals; self-reactive chemicals; and hazard not otherwise classified.
While EPA did not amend to include a definition of “combustible dust,” they commented that the OSHA definition of “combustible dust” applies: Combustible dust means finely divided solid particulates of a substance or mixture that pose a flash-fire hazard or explosion hazard when dispersed in air or other oxidizing media.
New Category Comparison
In addition, EPA has broadened the definitions of several hazardous categories, bringing the total count to 114. Table 1 presents a comparison of health hazards, while Table 2 provides a comparison of physical hazards. A full list can be viewed on the federal register.
Table 1. 2016 Tier II Health Hazard Categories vs New EPCRA Categories
| 2016 Category | New EPCRA Category |
| Acute Toxicity (any route of exposure) | Acute Toxicity, Oral—Category 1 |
| Acute Toxicity, Oral—Category 2 |
| Acute Toxicity, Oral—Category 3 |
| Acute Toxicity, Oral—Category 4 |
| Acute Toxicity, Dermal—Category 1 |
| Acute Toxicity, Dermal—Category 2 |
| Acute Toxicity, Dermal—Category 3 |
| Acute Toxicity, Dermal—Category 4 |
| Acute Toxicity, Inhalation—Category 1 |
| Acute Toxicity, Inhalation—Category 2 |
| Acute Toxicity, Inhalation—Category 3 |
| Acute Toxicity, Inhalation—Category 4 |
| Aspiration Hazard | Aspiration Hazard—Category 1 |
| Carcinogenicity | Carcinogenicity—Category 1 |
| Carcinogenicity—Sub-Category 1A |
| Carcinogenicity—Sub-Category 1B |
| Carcinogenicity—Category 2 |
| Germ Cell Mutagenicity | Germ Cell Mutagenicity—Category 1 |
| Germ Cell Mutagenicity—Sub-Category 1A |
| Germ Cell Mutagenicity—Sub-Category 1B |
| Germ Cell Mutagenicity—Category 2 |
| Reproductive Toxicity | Reproductive Toxicity—Category 1 |
| Reproductive Toxicity—Sub-Category 1A |
| Reproductive Toxicity—Sub-Category 1B |
| Reproductive Toxicity—Category 2 |
| Reproductive Toxicity—Effects on or via lactation |
| Respiratory or Skin sensitization | Respiratory sensitizer—Category 1 |
| Respiratory sensitizer—Sub-Category 1A |
| Respiratory sensitizer—Sub-Category 1B |
| Skin sensitizer—Category 1 |
| Skin sensitizer—Sub-Category 1A |
| Skin sensitizer—Sub-Category 1B |
| Serious Eye Damage or Eye Irritation | Serious eye damage—Category 1 |
| Eye irritation—Category 2 |
| Eye irritation—Sub-Category 2A |
| Eye irritation—Sub-Category 2B |
| Simple Asphyxiant | Simple Asphyxiant |
| Skin Corrosion or Irritation | Skin Corrosion—Category 1 |
| Skin Corrosion—Sub-Category 1A |
| Skin Corrosion—Sub-Category 1B |
| Skin Corrosion—Sub-Category 1C |
| Skin Irritation—Category 2 |
| Specific Target Organ Toxicity | Specific Target Organ Toxicity, Single Exposure-Category 1 |
| Specific Target Organ Toxicity, Single Exposure-Category 2 |
| Specific Target Organ Toxicity, Single Exposure-Category 3 |
| Specific Target Organ Toxicity, Prolonged Exposure-Category 1 |
| Specific Target Organ Toxicity, Prolonged Exposure-Category 2 |
| Hazard Not Otherwise Classified | Hazard Not Otherwise Classified |
Table 2. 2016 Tier II Physical Hazard Categories vs New EPCRA Categories
| 2016 Category | New EPCRA Category |
| Flammable (gases, aerosols, liquids, or solids) | Aerosols—Category 1 |
| Aerosols—Category 2 |
| Aerosols—Category 3 |
| Chemicals under pressure—Category 1 |
| Chemicals under pressure—Category 2 |
| Chemicals under pressure—Category 3 |
| Flammable Gases—Category 1A |
| Flammable Gases—Category 1B |
| Flammable Gases—Category 2 |
| Flammable Gases—Chemically Unstable Gas—Category 1A/A |
| Flammable Gases—Chemically Unstable Gas—Category 1A/B |
| Flammable Gases—Pyrophoric Gas—Category 1A |
| Flammable Liquids—Category 1 |
| Flammable Liquids—Category 2 |
| Flammable Liquids—Category 3 |
| Flammable Liquids—Category 4 |
| Flammable Solids—Category 1 |
| Flammable Solids—Category 2 |
| Combustible Dust | Combustible Dust |
| Corrosive to Metal | Corrosive to Metal—Category 1 |
| Not a Hazard Category in 2016 | Desensitized Explosives—Category 1 |
| Desensitized Explosives—Category 2 |
| Desensitized Explosives—Category 3 |
| Desensitized Explosives—Category 4 |
| Explosive | Explosives—Unstable |
| Explosives—Division 1.1 |
| Explosives—Division 1.2 |
| Explosives—Division 1.3 |
| Explosives—Division 1.4 |
| Explosives—Division 1.5 |
| Explosives—Division 1.6 |
| Gases Under Pressure (compressed gas) | Gas Under Pressure—Compressed Gas |
| Gas Under Pressure—Dissolved Gas |
| Gas Under Pressure—Liquefied Gas |
| Gas Under Pressure—Refrigerated liquefied gas |
| In contact with water emits flammable gas | In contact with water emits flammable gas—Category 1 |
| In contact with water emits flammable gas—Category 2 |
| In contact with water emits flammable gas—Category 3 |
| Organic Peroxides | Organic Peroxides—Type A |
| Organic Peroxides—Type B |
| Organic Peroxides—Type C |
| Organic Peroxides—Type D |
| Organic Peroxides—Type E |
| Organic Peroxides—Type F |
| Organic Peroxides—Type G |
| Oxidizer (liquid, solid or gas) | Oxidizing Gases-Category 1 |
| Oxidizing Liquids-Category 1 |
| Oxidizing Liquids-Category 2 |
| Oxidizing Liquids-Category 3 |
| Oxidizing Solids-Category 1 |
| Oxidizing Solids-Category 2 |
| Oxidizing Solids-Category 3 |
| Pyrophoric (liquid or solid) | Pyrophoric Liquids—Category 1 |
| Pyrophoric Solids—Category 1 |
| Pyrophoric Gas | Classified as Flammable Gas in the 2024 OSHA HCS. |
| Self-heating | Self-heating—Category 1 |
| Self-heating—Category 2 |
| Self-reactive | Self-reactive—Type A |
| Self-reactive—Type B |
| Self-reactive—Type C |
| Self-reactive—Type D |
| Self-reactive—Type E |
| Self-reactive—Type F |
| Self-reactive—Type G |
| Hazard Not Otherwise Classified | Hazard Not Otherwise Classified |
Compliance with the new regulations
To ensure compliance with the revised EPCRA regulations, facilities should obtain updated SDSs that that comply with the 2024 OSHA Hazard Communication Standard. This will be necessary to properly complete the Tier II report due March 1, 2027. Manufacturers, importers, distributors, and employers are required to comply with applicable requirements based on the timelines listed in Table 3.
Table 3. 2024 OSHA Hazard Communication Standard, Effective July 19, 2024
| Compliance Date | Requirements | Who |
| January 19, 2026 | Update labels and SDSs for substances | Chemical manufacturers, importers, distributors, employers |
| July 20, 2026 | Update workplace labels, hazard communication program, and training as necessary | Employers |
| July 19, 2027 | Update labels and SDSs for mixtures | Chemical manufacturers, importers, distributors, employers |
| January 19, 2028 | Update workplace labels, hazard communication program, and training as necessary | Employers |
| Transition Period – July 19, 2024 to compliance date | May comply with either 29 CFR 1910.1200 (this final standard), or the previous standard, or both | Chemical manufacturers, importers, distributors, employers |
For more information, please contact your local Trinity office or call Trinity Consultants at 800.229.6655.
