In June 2025, Louisiana lawmakers passed Act 458, a sweeping change to how Legacy environmental damage claims are handled. The law takes full effect on September 1, 2027, and it fundamentally reshapes how soil contamination and groundwater contamination are addressed across the state.
Why does this matter to landowners? Because Act 458 replaces court-driven cleanup decisions with state-controlled, risk-based cleanup plans. Under the new framework, the government—not judges or juries—will determine how much contaminated soil must be remediated and how much pollution can remain in place.
For property owners dealing with oil field pollution or other industrial contamination, this shift comes with major consequences: higher proof standards, capped damages, and long-term responsibility for contamination deemed “acceptable.” Most importantly, landowners who file suit before September 1, 2027 can preserve their rights under the current, more landowner-friendly law.
This blog will explain what risk-based cleanup means, how Act 458 changes the rules, and what steps Louisiana landowners should take now.
A Quick History: Act 312 to Act 458
For nearly two decades, Act 312 governed environmental damage claims in Louisiana. Under this law:
- Landowners could sue operators for full remediation of contaminated soil under court supervision.
- Judges and juries played a central role in determining cleanup standards.
- The burden of proof was relatively low—“preponderance of the evidence.”
This structure gave landowners leverage to demand cleanup that restored property to its original condition, particularly in cases involving oil field pollution.
Act 458 (2025 Amendments) Highlights
Act 458 dramatically alters that balance by:
- Transferring cleanup authority to the government—specifically, to the Louisiana Department of Energy and Natural Resources (LDENR)
- Introducing risk-based cleanup, allowing certain contamination to remain
- Raising the proof standard to “clear and convincing evidence”
- Capping non-remediation damages at three times fair market value
The result is the landowner’s rights will be weakened.
Defining Risk-Based Cleanup
Risk-based cleanup allows regulators to leave contaminated soil in place if scientific testing shows it poses minimal risk to human health or the environment. Instead of removing all contamination, the focus shifts to managing exposure.
LDENR evaluates sites using benchmarks tied to human contact, groundwater contamination pathways, and environmental impact. If contamination falls below those thresholds, it may remain indefinitely.
This approach differs sharply from full cleanup, where contaminated soil is removed or remediated to background levels. While risk-based cleanup can reduce upfront costs, it often leaves landowners with permanent restrictions, monitoring obligations, and diminished property value.
The Risk-Based Cleanup Process Under Act 458
Once a claim proceeds under Act 458, LDENR conducts site testing and reviews environmental data. The agency compares findings against Louisiana’s Risk Evaluation/Corrective Action Program (RECAP) standards, which guide acceptable exposure levels. This assessment determines whether contamination presents a high, moderate, or low risk.
Remediation Plan Development
LDENR then develops a remediation plan that focuses solely on high-risk areas. Zones considered low risk may be left untouched, but managed through:
- Deed restrictions
- Long-term monitoring
- Land-use limitations
These controls typically remain attached to the property, even after a sale.
Court Adoption of the Plan
Courts must adopt the agency’s plan unless the landowner proves, by clear and convincing evidence, that a better plan exists. Appeals are streamlined directly to the First Circuit Court of Appeal to ensure uniform application statewide.
Impact on Landowners
Under Act 458, courts no longer decide what cleanup looks like. That authority rests almost entirely with LDENR, reducing a landowner’s ability to demand full remediation of contaminated soil.
Residual Contamination Risks
Even “low-risk” contamination can create long-term problems. Some of those issues may include:
- Reduced property value
- Difficulty selling or refinancing
- Increased scrutiny from insurers and lenders
- Barriers to redevelopment or agricultural use
Residual groundwater contamination can also migrate over time, creating future liability.
Higher Burden, Lower Damages
Act 458 raises the proof standard to clear and convincing evidence, making claims harder to win. At the same time, damages unrelated to cleanup are capped at three times the property’s fair market value, limiting compensation for loss of use, stigma, or future development potential.
This change carries drawbacks for landowners. Some contamination may remain on the property indefinitely, creating long-term monitoring and compliance obligations, reducing leverage and financial recovery in disputes, and potentially imposing permanent land-use restrictions that can affect resale, redevelopment, or financing.
The Critical Filing Deadline
Landowners who file claims well before September 1, 2027 remain under Act 312 and preserve stronger rights. Waiting too long means forfeiting court-driven cleanup standards and accepting state-controlled risk assessments.
Next Steps for Landowners
If your property may be affected by soil contamination or groundwater contamination, now is the time to act. Consulting experienced environmental counsel early can make the difference between full remediation and permanent risk-based controls.
Talbot, Carmouche & Marcello can help you evaluate contamination risks and file claims before September 1, 2027 to preserve Act 312 rights.
Don’t Wait to File
Act 458 represents one of the most significant shifts in Louisiana environmental law in decades. By embracing risk-based cleanup, the state has prioritized regulatory “efficiency” over full restoration, placing new burdens and long-term risks on landowners.
With the September 1, 2027 deadline approaching, waiting could cost you control, compensation, and certainty. If you suspect contamination on your property, take action now to protect your rights under existing law.
Contact Talbot, Carmouche & Marcello today for a no-cost case review and learn how to safeguard your land before the rules change.