PlainEnviro

EPA TRI Chemical

1,4-Dioxane

CAS Number: 123-91-1

Total releases
4.8M lbs
Number of facilities
82
Carcinogen
Yes
PBT substance
No
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Carcinogen

According to the EPA Toxics Release Inventory, 1,4-Dioxane (CAS 123-91-1) is disclosed by 82 Form R facilities totaling 4.8M lbs of reported releases. The TRI extract marks this chemical with a carcinogen classification flag. TRI pounds are self-reported disclosure totals, not a measured public-health risk score.

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1,4-Dioxane (CAS 123-91-1) is a chemical tracked by the EPA Toxics Release Inventory (TRI) program under Section 313 of the Emergency Planning and Community Right-to-Know Act. The TRI requires industrial facilities above specified threshold quantities to disclose annual manufacturing, processing, and otherwise-used volumes, along with quantities released to air, water, land, and off-site transfers.

The carcinogen flag above reflects an assessment from EPA, the International Agency for Research on Cancer, or the National Toxicology Program, not a TRI-specific determination. The largest individual disclosure in the current dataset comes from HUNTSMAN INTERNATIONAL LLC in TX at 2.0M lbs.

TRI volumes are self-reported estimates, not measured stack emissions, and each pound counts equally regardless of chemical toxicity, so total pounds should not be equated with total risk. Inclusion of a chemical or facility in the TRI does not itself establish a health hazard; it documents the public right-to-know record. Consult EPA's IRIS (Integrated Risk Information System) and the Agency for Toxic Substances and Disease Registry for health-effect summaries.

MIXED pathway mix

1,4-Dioxane: how the 4.8M lbs splits

4.8M lbs across all reported pathways

  • Off-site Transfers2.3M lbs48.5%
  • Land Disposal1.8M lbs37.8%
  • Water Discharges361.0K lbs7.6%
  • Air Releases289.7K lbs6.1%

1,4-Dioxane's 4.8M lbs Form-R total is MIXED, with off-site transfers making up 48.5% of the bar. Next segment: land disposal at 37.8%.

Trend & Where It's Reported

Reported Release Trend

Between 2019 and 2023, cumulative annual 1,4-Dioxane releases across all reporting facilities increased by 5% (653.6K lbs → 688.9K lbs). Year-to-year swings reflect facility openings/closures and reporting changes as much as underlying activity.

Geographic Concentration

Reporting for 1,4-Dioxane is highly concentrated: Texas accounts for 73.3% of the reported total (9 facilities). Next: Oregon.

  • Texas 3.5M lbs
  • Oregon 278.4K lbs
  • South Carolina 235.9K lbs
  • New Jersey 182.4K lbs
  • West Virginia 156.5K lbs
Industry Sources

Reporting for 1,4-Dioxane is highly concentrated by industry: Chemicals facilities account for 60.8% of the reported total (50 facilities). Next: Hazardous Waste.

  • Chemicals 2.9M lbs
  • Hazardous Waste 1.8M lbs
  • Other 24.7K lbs
  • Plastics and Rubber 9.4K lbs
  • Nonmetallic Mineral Product 8.4K lbs

Which facilities release the most of this chemical?

Facilities with the largest reported releases of 1,4-Dioxane. Up to 50 shown.

# Facility Release (lbs)
1 Huntsman International LLC
2.0M lbs
2 Union Processing Systems LLC
1.3M lbs
3 Chemical Waste Management of the Northwest Inc.
277.1K lbs
4 Coim USA Inc
220.2K lbs
5 Apg Polytech LLC
156.5K lbs
6 Tm Deer Park Services LP
152.7K lbs
7 Alpek Polyester USA Llc-Columbia Site
136.4K lbs
8 Stepan Co Millsdale Road
105.6K lbs
9 Indorama Ventures
95.4K lbs
10 Alpek Polyester USA LLC Cooper River Plant
66.3K lbs
11 Eastman Chemical Co Tennessee Operations
43.5K lbs
12 Vickery Environmental Inc.
40.1K lbs
13 Union Carbide Corp Seadrift Plant
26.8K lbs
14 Alpek Polyester USA LLC
24.5K lbs
15 Eq Detroit Inc
24.5K lbs
16 St Charles Operations (taft/star) Union Carbide Corp
23.0K lbs
17 Emerald Services Inc
17.0K lbs
18 Nan Ya Plastics Corp America
11.8K lbs
19 Stepan Co
11.8K lbs
20 Mitsubishi Chemical America Inc.
9.1K lbs
21 Alpek Polyester Mississippi Inc
7.0K lbs
22 Auriga Polymers Inc-Spartanburg Facility
6.7K lbs
23 Saint Gobain Abrasives Inc
5.0K lbs
24 Eastman Chemical Co South Carolina Operations
4.2K lbs
25 Starpet Inc
3.5K lbs
26 Buzzi Unicem Usa-Greencastle Plant
2.9K lbs
27 E R Carpenter LP
2.3K lbs
28 Basf Corp
2.1K lbs
29 Systech Environmental Corp
2.0K lbs
30 Lexmark International Inc
1.8K lbs
31 Veolia Wts Solutions USA Inc.
1.5K lbs
32 Lacamas Laboratories Inc
1.3K lbs
33 Curia Missouri-Springfield (formerly Amri-Missouri Inc.)
1.1K lbs
34 Corden Pharma Colorado Inc
1.0K lbs
35 Cambrex Charles City Inc
998 lbs
36 Huntsman Petrochemical LLC Port Neches Facility
887 lbs
37 Phenomenex Inc.
862 lbs
38 Patheon Api Services Inc.
814 lbs
39 Eco-Services Operations
778 lbs
40 Solvay USA LLC
630 lbs
41 Clean Harbors Environmental Services Inc
453 lbs
42 Giant Cement Co
420 lbs
43 US Army Picatinny Arsenal
270 lbs
44 Polynt Composites USA Inc.
259 lbs
45 Microdyn-Nadir Corp
255 lbs
46 Curia Wisconsin Inc.
209 lbs
47 Buckman Laboratories Inc.
208 lbs
48 Clean Harbors el Dorado LLC
127 lbs
49 Pci Synthesis
110 lbs
50 Curia Rensselaer Inc.
105 lbs

Frequently Asked Questions

What is 1,4-Dioxane in the EPA TRI? ▼
1,4-Dioxane (CAS Number: 123-91-1) is a chemical tracked by the EPA Toxic Release Inventory (TRI) program. The TRI extract marks it with a carcinogen classification flag based on EPA/IARC/NTP listings. 82 facilities in the United States report releasing this chemical to the EPA.
How much 1,4-Dioxane is disclosed in U.S. TRI filings? ▼
U.S. facilities have reported a total of 4.8M lbs of 1,4-Dioxane releases to the EPA Toxic Release Inventory across 82 facilities. Release quantities are self-reported estimates covering air, water, land, and off-site transfers. They are disclosure totals, not toxicity-weighted harm scores.
How does EPA TRI classify 1,4-Dioxane? ▼
1,4-Dioxane carries a carcinogen classification flag in the TRI database (drawn from EPA, IARC, or NTP listings). TRI classification flags document inventory listing status; they are not a site-specific exposure or health diagnosis. For health-effect summaries see EPA IRIS and ATSDR toxicological profiles.
Which facilities disclose the most 1,4-Dioxane? ▼
Huntsman International LLC in TX reports the largest disclosed release of 1,4-Dioxane in this dataset, at 2.0M lbs. Most reporting facilities for this chemical fall under chemicals. Release data is self-reported annually to the EPA under the TRI program. View the full list of 82 facilities on this page.
What is the CAS number for 1,4-Dioxane? ▼
The CAS (Chemical Abstracts Service) Registry Number for 1,4-Dioxane is 123-91-1. CAS numbers are unique numerical identifiers assigned to every chemical substance described in the open scientific literature. This identifier is used to search scientific databases and regulatory filings.

Related Guides

Understanding TRI Data
How the Toxic Release Inventory works
Biggest Polluters in America
Which facilities release the most toxics
How to Check Environmental Quality
Step-by-step guide to checking your local environment

Health Information

Carcinogen Classification: This chemical is classified as a known or suspected carcinogen by the EPA under the Toxic Release Inventory program. This classification is based on evaluations by agencies including the International Agency for Research on Cancer (IARC), the National Toxicology Program (NTP), and the EPA itself.

Data comes from the EPA Toxic Release Inventory (TRI) program. Release quantities are self-reported by facilities and may represent estimates. The total shown aggregates reports across all facilities and reporting years.

PlainEnviro presents this data without advocacy framing. The presence of a chemical in the TRI database does not by itself indicate a health risk at current exposure levels. For health-related questions about specific chemical exposures, consult your local health agency or a toxicologist.

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Data sourced from the U.S. Environmental Protection Agency (EPA). See our methodology for details. Retrieved and formatted by PlainEnviro

Disclaimer: This information is provided for informational purposes only and does not constitute professional advice. Data is sourced from the EPA Toxic Release Inventory (TRI). Consult a qualified professional before making decisions based on this data.

Read our methodology - how this data is sourced, computed, and verified.