PlainEnviro

EPA TRI Chemical

Styrene Oxide

CAS Number: 96-09-3

Total releases
838 lbs
Number of facilities
2
Carcinogen
Yes
PBT substance
No
Verify at EPA TRI →
Carcinogen

According to the EPA Toxics Release Inventory, Styrene Oxide (CAS 96-09-3) is disclosed by 2 Form R facilities totaling 838 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.

View saved records

Styrene Oxide (CAS 96-09-3) 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 KEYSTONE CEMENT CO in PA at 505 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

Styrene Oxide: how the 838 lbs splits

838 lbs across all reported pathways

  • Off-site Transfers507 lbs60.5%
  • Air Releases331 lbs39.5%

Styrene Oxide's 838 lbs Form-R total is MIXED, with off-site transfers making up 60.5% of the bar. Next segment: air releases at 39.5%.

Trend & Where It's Reported

Reported Release Trend

Between 2019 and 2021, cumulative annual Styrene Oxide releases across all reporting facilities decreased by 99% (221 lbs → 3 lbs). Year-to-year swings reflect facility openings/closures and reporting changes as much as underlying activity.

Geographic Concentration

Reporting for Styrene Oxide is highly concentrated: Pennsylvania accounts for 60.3% of the reported total (1 facility). Next: South Carolina.

  • Pennsylvania 505 lbs
  • South Carolina 333 lbs
Industry Sources

Reporting for Styrene Oxide is highly concentrated by industry: Nonmetallic Mineral Product facilities account for 100.0% of the reported total (2 facilities).

  • Nonmetallic Mineral Product 838 lbs

Which facilities release the most of this chemical?

Facilities with the largest reported releases of Styrene Oxide. Up to 50 shown.

# Facility Release (lbs)
1 Keystone Cement Co
505 lbs
2 Giant Cement Co
333 lbs

Frequently Asked Questions

What is Styrene Oxide in the EPA TRI? ▼
Styrene Oxide (CAS Number: 96-09-3) 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. 2 facilities in the United States report releasing this chemical to the EPA.
How much Styrene Oxide is disclosed in U.S. TRI filings? ▼
U.S. facilities have reported a total of 838 lbs of Styrene Oxide releases to the EPA Toxic Release Inventory across 2 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 Styrene Oxide? ▼
Styrene Oxide 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 Styrene Oxide? ▼
Keystone Cement Co in PA reports the largest disclosed release of Styrene Oxide in this dataset, at 505 lbs. Most reporting facilities for this chemical fall under nonmetallic mineral product. Release data is self-reported annually to the EPA under the TRI program. View the full list of 2 facilities on this page.
What is the CAS number for Styrene Oxide? ▼
The CAS (Chemical Abstracts Service) Registry Number for Styrene Oxide is 96-09-3. 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.

Related

Browse all → | Rankings →
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.