When crude oil hits the dirt on a Texas lease, Statewide Rule 91 (16 TAC §3.91) sets the cleanup. You remove free oil immediately, map how far the contamination goes, bring up all soil over 1.0% total petroleum hydrocarbons (TPH) by weight, deal right away with anything over 5.0%, and reach 1.0% TPH within one year of the spill. Spills over five barrels also get a phone notice to the RRC district office under Rule 20 and a Form H-8 report.
Rule 91 is still in force. The Railroad Commission amended it effective July 1, 2025, at the same time its new Chapter 4 waste rules replaced Statewide Rule 8. The rest of this guide covers what the rule says, where it stops applying, and how the work usually unfolds on spill day. It’s educational, not legal advice. Your district office and your environmental contractor have the final word on a specific site.
Rule 91 after July 1, 2025: what changed and what didn’t
The amended text, published in the Texas Register on January 3, 2025 and effective July 1, 2025, carries the 1.0% and 5.0% TPH levels, the one-year deadline and the 5- and 25-barrel reporting tiers. The visible change is the frame around it: Rule 91’s scope now points to the definitions in §4.110 of the new Chapter 4.
Chapter 4, Subchapter A, is the Commission’s rewrite of its oil and gas waste rules. It took over from Rule 8 (§3.8) and folded in the produced-water recycling rule (§3.57). For a spill crew, the part you’ll notice is waste handling. If excavated soil leaves the lease, expect Chapter 4’s waste profile and manifest requirements to apply, with a manifest signed by the generator, transporter and receiver, and records kept for at least three years. Confirm the details with your disposal facility before the first truck rolls.
Does Rule 91 apply to your spill?
Rule 91 is narrower than people assume. It covers soil in non-sensitive areas contaminated by crude oil spills from exploration, development and production, including transportation. It does not cover:
- Hydrocarbon condensate spills (the light liquids produced with natural gas).
- Crude oil spills in sensitive areas.
- Contamination that happened, wholly or partly, before the rule took effect.
For all three, cleanup is set case by case and the operator has to consult the district office on standards, methods and reporting.
“Sensitive area” is broad in West Texas terms. The rule lists shallow groundwater or pathways to deeper groundwater, and proximity to surface water, which it spells out as lakes, rivers, streams, dry or flowing creeks, irrigation canals, stock tanks and wetlands. Wildlife refuges, parks, and commercial or residential areas count too. A dry draw across the lease road can put a spill outside the standard rule.
What the cleanup standard requires, step by step
| Step | What Rule 91 says | Paragraph |
|---|---|---|
| Remove free oil | All free oil removed immediately for reclamation or disposal, to limit how deep it soaks in | (c)(1) |
| Delineate | Once free oil is off, immediately map the contaminated area vertically and horizontally. “Contaminated” means more than 1.0% TPH by weight | (c)(2) |
| Excavate | At minimum, all soil over 1.0% TPH brought to the surface for disposal or remediation | (c)(3) |
| Handle soil over 5.0% TPH | Immediately mix in place to 5.0% or less, haul to an approved disposal site, or move to secure interim storage designed to keep stormwater from carrying it off. Plastic underneath and on top is one accepted method | (c)(4) |
| Reach the final level | 1.0% TPH as soon as technically feasible and no later than one year after the spill. Any technically sound method is allowed | (d)(1) |
| If bioremediating on site | Mix the soil to a uniform layer no more than 18 inches deep and no more than 5.0% TPH | (d)(2) |
For scale, 1.0% by weight is 10,000 mg/kg. That’s a field-level cleanup number, which is why lab samples and a defensible delineation matter more than how the ground looks after the dozer leaves.
The rule also lets the Commission approve alternatives for good cause, such as new technology, if the operator shows in writing that they protect the environment at least as well.
Reporting a crude oil spill in Texas: Rule 20, Form H-8 and the final report
Reporting depends on how much crude came out.
| Spill size (crude oil to soil) | RRC notice | Paperwork |
|---|---|---|
| 5 barrels or less | Not required for soil | None, but the soil still has to be cleaned up to the Rule 91 standard |
| More than 5 barrels | Immediate notice to the district office under Rule 20, followed by a letter describing the incident | Form H-8 with area (sq ft), maximum depth (ft) and volume (cu yd) of soil over 1.0% TPH; signed statements on excavation and on soil over 5.0%; cleanup method; estimated completion date |
| More than 25 barrels | Same as above | Everything above, plus a final report when cleanup is done, with sample analyses showing the final level was met |
| Any amount into water | Must be reported to the Commission | Per district office instructions |
Rule 20 (§3.20) is the older notice rule underneath all of this. It requires immediate notice of any fire, leak, spill or break to the district office by telephone. It says the report on oil losses is needed only when the loss exceeds five barrels in the aggregate. The follow-up letter covers location by county, survey and property, the volume lost (estimated if needed) and the remedial steps taken.
A typical spill-day timeline on a Texas lease
| When | What happens | Who usually does it |
|---|---|---|
| First minutes | Stop the source, keep oil from spreading, keep it out of draws and ditches | Lease operator, pumper, crew on site |
| Same day | Call the district office if over 5 barrels (Rule 20). Pick up free oil | Operator; vac truck |
| Right after free oil is off | Delineate the 1.0% TPH footprint, vertical and horizontal | Environmental contractor with sampling |
| Immediately on excavation | Mix, haul or securely store anything over 5.0% TPH so rain can’t spread it | Remediation contractor |
| After excavation | File Form H-8 for spills over 5 barrels | Operator’s regulatory staff |
| Within one year | Reach 1.0% TPH. Over 25 barrels, file the final report with sample analyses | Operator and contractor |
Treatment and disposal options for oil-contaminated soil
Rule 91 doesn’t pick the method. It sets the endpoint and lets the operator choose any technically sound way to get there. The research literature groups the options into physical and thermal treatment (such as thermal desorption and soil vapor extraction), chemical oxidation, and biological approaches like biostimulation and bioaugmentation, according to a 2022 review in 3 Biotech. The same review explains why speed matters: petroleum compounds bind to soil particles and reduce the oxygen and water moving through the soil, which slows natural breakdown.
On Texas leases, the common choices are hauling to an approved disposal facility or on-site bioremediation within Rule 91’s 18-inch, 5.0% TPH limits. Which one makes sense depends on volume, distance to disposal, soil type and whether the site is sensitive. That call belongs to the operator and an environmental contractor.
The cheaper fix: keep crude off the soil in the first place
Every requirement above starts the moment crude reaches dirt. A leak onto a liner or mat is a cleanup of the liner. The same leak onto caliche turns into delineation, excavation, sampling, possibly a Form H-8, and up to a year of follow-through. Our guide on the first hour of a spill covers why containment that is already in place beats containment you go and fetch.
Site Safe Solutions doesn’t do spill cleanup, soil remediation or regulatory reporting. What we do is the prevention hardware. Containment systems go under tank batteries, separators and other fixed equipment. Custom-sized drive-over Fast Mats cover temporary stations, service trucks and small fluid transfers where most minor leaks start. If you’re looking at a location and wondering where the next spill would hit bare ground, talk to our team about closing those gaps across your Permian Basin sites.
