EPA TRI Facility · Natural Gas Processing
Markwest Hidalgo Plant
Orla, TX · Parent: Marathon Petroleum Corp
- Total releases
- 219.7K lbs
- Chemicals reported
- 11
- Carcinogens
- 4
- Primary pathway
- Off-site Transfers
Markwest Hidalgo Plant has reported 219.7K lbs of toxic releases across 11 chemicals to the EPA Toxic Release Inventory, based on annual facility disclosures from 2019 through 2023. Of the chemicals reported, 4 are classified as carcinogens, representing 36% of the facility's chemical profile. The facility operates in the Natural Gas Processing sector. The primary release pathway is off-site transfers, accounting for 100% of total releases. All release data shown below is self-reported to the EPA under the Emergency Planning and Community Right-to-Know Act (EPCRA) Section 313.
Markwest Hidalgo Plant files annual Form R disclosures to the EPA Toxics Release Inventory under EPCRA Section 313, classified under NAICS 211130 (Natural Gas Processing). Across 2 years of records spanning 2022–2023, the site has disclosed 219.7K lbs in cumulative toxic releases across 11 distinct chemicals, 4 of which (36%) carry a carcinogenic classification.
The dominant release pathway is off-site transfers at 219.7K lbs (100.0% of total volume). Between 2022 and 2023, reported totals decreased by 51% - from 147.1K lbs to 72.6K lbs. The facility is operated under parent company Marathon Petroleum Corp.
TRI Form R values are self-reported estimates, not measured stack emissions, and treat every pound of reported chemical equally regardless of toxicity. Inclusion in the TRI database does not establish a health risk to nearby residents; it documents the annual reporting record that Markwest Hidalgo Plant has filed with the EPA under federal community right-to-know requirements.
Quick Facts
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See how Markwest Hidalgo Plant stacks up against nearby facilities and the typical reporter.
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69% less than the comparison
Comparison reflects reported pounds and chemical counts, not toxicity or health risk. Averages cover facilities reporting any release.
How does this facility release toxic chemicals?
How Markwest Hidalgo Plant releases toxic chemicals into the environment. Total: 219.7K lbs.
Emissions Trend Summary
From 2022 to 2023, total releases decreased by 51% (147.1K lbs to 72.6K lbs).
Reported total releases by year
Markwest Hidalgo Plant - annual TRI totals
- 2022 0
2022
0 million lbs
- 2023 0
2023
0 million lbs
What this shows Year-over-year reported totals. TRI figures are self-reported estimates and can swing with production levels, waste-rock handling and reporting changes, not only with emissions controls.
| Year | Total | Chemicals |
|---|---|---|
| 2022 | 147.1K lbs | 10 |
| 2023 | 72.6K lbs | 4 |
Chemical Releases
Aggregated across all reporting years (2022–2023). 4 of 11 chemicals are carcinogens. Sorted by total release volume.
| Chemical | Total | Flags |
|---|---|---|
| Ethylene glycol | 67.1K lbs | - |
| Naphthalene | 63.9K lbs | Carcinogen |
| Xylene (mixed isomers) | 32.0K lbs | - |
| Toluene | 16.0K lbs | - |
| 1,2,4-Trimethylbenzene | 16.0K lbs | - |
| n-Hexane | 13.6K lbs | - |
| Benzene | 8.0K lbs | Carcinogen |
| Ethylbenzene | 1.6K lbs | Carcinogen |
| Cumene | 1.6K lbs | Carcinogen |
| Cyclohexane | 0 lbs | - |
| Methanol | 0 lbs | - |
Location
Other Facilities in Texas
About TRI Data
Data as of 2023 reporting year. Source: U.S. Environmental Protection Agency (EPA) Toxic Release Inventory.
Data comes from the EPA Toxic Release Inventory (TRI) program. Facilities that manufacture, process, or otherwise use listed toxic chemicals above threshold amounts are required to report annually to the EPA.
Release quantities are self-reported by the facility and may represent estimates rather than exact measurements. "Total releases" includes releases to air, water, land, and off-site transfers for disposal. Quantities shown here are aggregated across all available reporting years.
PlainEnviro presents this data without advocacy framing. The presence of a facility in the TRI database does not by itself indicate a health risk. For site-specific health questions, consult your local environmental or health agency.
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Explore More Data for Texas
What to do with this facility's data
Use this facility profile as a starting point, then check how it compares.
- See whether releases reported by Markwest Hidalgo Plant are rising or falling over time. View trends
- This facility ranks #3,084 of 25,902 TRI facilities nationwide by total reported releases. Ranking reflects reported pounds, not toxicity or health risk. See the full rankings
- Check Texas's statewide profile for the full picture: total facilities, water systems, and Superfund sites. View Texas profile
TRI release totals are self-reported estimates submitted to the EPA, not independently measured stack emissions; a high rank reflects reported volume, not necessarily local health risk.
Read our methodology - how this data is sourced, computed, and verified.
Related
Sources & how this page was built
Every figure on this page traces to public, federal-government data on Markwest Hidalgo Plant. The records below are the primary sources; our methodology explains how they are joined, computed, and verified.
- EPA Toxics Release Inventory (TRI) Basic Data Files - annual self-reported chemical-release filings. epa.gov
- EPA TRI Program, chemical & reporting reference - what each chemical is and how releases are counted. epa.gov
- EPA Facility Registry Service (FRS) - authoritative facility location and identity. epa.gov
- EPA Enforcement & Compliance History Online (ECHO) - regulatory and compliance context. echo.epa.gov
- EPA Envirofacts - the EPA data warehouse that exposes these datasets. enviro.epa.gov
Retrieved and formatted by PlainEnviro Editorial. TRI release totals are self-reported estimates, not measured stack emissions.
According to the U.S. Environmental Protection Agency, the Toxics Release Inventory has required annual industrial disclosure since its creation under the Emergency Planning and Community Right-to-Know Act in October 1986, and this facility's record is drawn from PlainEnviro's database of more than 25,000 EPA-tracked facilities through the 2023 reporting year; see our methodology for full source citations and refresh cadence.