Environmental Claims: Liability, Defenses, and Deadlines

Liability for environmental claims runs broad and often backward in time: under the federal Superfund statute and its companions, current owners, former owners, waste generators, and transporters can each be forced to pay cleanup costs on a strict, joint and several basis, meaning fault does not have to be proved and any one responsible party can be made to cover the whole bill. That is the core of environmental claims liability, and it explains why the defenses, due diligence protections, and settlement tools built around it matter as much as the underlying rules. A single Superfund site can generate tens of millions of dollars in remediation costs, and daily civil penalties for Clean Air Act violations now reach $124,426 per violation.¹

Who Can Be Held Liable

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), enacted in 1980, identifies four categories of potentially responsible parties. The net is deliberately wide, and any party falling into one of these groups faces strict liability for contamination at a covered site.²

Current owners and operators of a facility where hazardous substances are present. You can be liable even if you had nothing to do with the contamination — buying a contaminated property is enough.
Past owners and operators who held the site at the time hazardous substances were disposed of there. A company that ran a factory in the 1960s and sold it decades ago stays on the hook for what happened during its tenure.
Arrangers, meaning anyone who arranged for disposal or treatment of hazardous substances. A manufacturer that hired a hauler to take chemical byproducts to a dump qualifies. Courts have drawn a line: selling a useful product that happens to contain hazardous ingredients is not the same as arranging for disposal.³
Transporters who took hazardous substances to a disposal site they selected. The word “selected” matters. A trucking company that followed the shipper’s instructions to a specific landfill generally has less exposure than one that chose the dump itself.

Two features of this liability are unusual and consequential. Liability is strict, so the government does not need to prove negligence or intent. Liability is also joint and several, so any single responsible party can be made to pay the entire cleanup cost and then pursue the others for their share.³ The Supreme Court has recognized one escape: if a party can show the harm is divisible and its contribution reasonably separable from the whole, its liability can be limited to its portion. The burden of proving a reasonable basis for that split falls on the party trying to avoid full liability.

CERCLA is also retroactive. It reaches contamination that occurred before the statute was enacted in 1980.⁴ A company that disposed of waste legally in 1970 under the standards of the day can still face full cleanup liability today.

What Kinds of Claims Get Brought

Environmental claims cluster into three broad categories, each with its own framework.

Site Contamination and Cleanup

These are the classic Superfund claims. When hazardous substances are present at a facility and a release has occurred or is threatened, CERCLA authorizes the government to recover all costs of removal or remedial action from responsible parties.² Private parties who incur their own cleanup costs consistent with the National Contingency Plan can also recover from other responsible parties. Identifying potentially responsible parties and allocating costs among them can take years at large sites with dozens or hundreds of contributors.

Pollution Discharge and Exposure

These claims target ongoing or recent releases into air or water, typically when a facility discharges without a permit or exceeds the limits of one it holds. The Clean Water Act governs water discharges;⁵ the Clean Air Act governs atmospheric emissions. Unlike Superfund cases, which often address historical contamination, discharge claims usually go after current violations and seek both penalties and orders to stop the pollution.

Natural Resource Damages

Natural resource damages address injury to publicly held resources: waterways, fisheries, wildlife, groundwater, wetlands. CERCLA defines natural resources broadly as land, fish, wildlife, air, water, groundwater, drinking water supplies, and similar resources belonging to or managed by the federal government, a state, a local government, or an Indian tribe.⁶ Only designated government trustees can bring these claims on behalf of the public.

The measure of damages includes the cost of restoring the injured resource to its pre-contamination condition, compensation for the public’s loss during recovery, and the reasonable cost of assessing the damage.⁷ Any money recovered must go toward restoring, replacing, or acquiring the equivalent of the damaged resource. It cannot be diverted to other government purposes.²

Who Can Sue

Enforcement runs on two tracks: government agencies carry the primary load, and private citizens serve as a backstop. Injured neighbors have a third path through traditional tort law.

Government Enforcement

The EPA and its state counterparts bring enforcement actions to compel compliance and recover cleanup costs. Actions can produce civil penalties, mandatory cleanup orders, or both. Inflation-adjusted maximum daily penalties for Clean Air Act violations stand at $124,426 per day per violation, while Clean Water Act penalties reach $68,445 per day.¹ Penalties are designed to punish the violation and strip away any economic advantage the violator gained by cutting corners.

Citizen Suits

Most major environmental statutes let private individuals and organizations sue polluters directly, or sue the EPA for failing to carry out a mandatory duty. Under the Clean Water Act, any citizen can file suit against a party alleged to be violating an effluent standard or a related compliance order.⁸ The Clean Air Act provides a parallel mechanism.⁹

Before filing, a citizen must send a 60-day notice of intent to the alleged violator, the EPA, and the relevant state agency. That cooling-off period lets the violator come into compliance and gives government enforcers a chance to step in. If a government agency has already commenced and is diligently prosecuting its own enforcement action covering the same violations, the citizen suit is barred. The scope of that bar is narrow: it blocks claims only for the specific violations the government is actively pursuing, not different pollutants or different regulatory standards at the same facility. Under the Clean Air Act, only a government civil or criminal case filed in court triggers the bar; administrative enforcement alone is not enough. Under the Clean Water Act, administrative penalties can sometimes block a citizen suit for penalties, though injunctive relief may remain available.⁸

Prevailing plaintiffs in citizen suits can recover attorney fees and litigation costs when the court finds an award appropriate. Environmental statutes typically authorize fees for “any party,” and in practice, nonprofit organizations that bring successful enforcement actions recover fees in nearly all circumstances when the suit was brought in good faith.

Private Tort Claims

Separate from citizen suits, individuals who suffer personal injury or property damage from pollution can bring traditional tort claims under state common law. A property owner whose land is contaminated by a neighboring factory can sue under nuisance (interference with the use and enjoyment of land), trespass (physical invasion of property by pollutants), or negligence (failure to exercise reasonable care). Unlike statutory claims, these require some showing of fault or unreasonable conduct, and they focus on compensating the injured party rather than enforcing regulatory compliance. A homeowner whose well water is contaminated by a neighboring industrial site can sue for diminished property value, cleanup costs on their own land, and health-related damages. In cases involving reckless or intentional misconduct, punitive damages may be available, though the bar is significantly higher than for ordinary compensatory damages.

Remedies Available

Monetary Relief

Monetary remedies take several forms depending on who brings the claim. In government enforcement, the primary financial tool is civil penalties assessed per day per violation. In private tort suits, compensatory damages cover property damage, diminished land value, cleanup costs, and personal injury. In statutory cost recovery actions, a party that has paid for cleanup can recover those costs from other responsible parties.

Injunctive Relief

Courts can order defendants to stop polluting, install specific pollution control equipment, or carry out full site remediation under court supervision. Injunctive relief is often the most consequential remedy because it forces operational changes that last long after a penalty check clears. A court might order a factory to retrofit its wastewater treatment system, a mine operator to restore damaged waterways, or a facility to install air monitoring equipment along its perimeter.

Supplemental Environmental Projects

In enforcement settlements, defendants can sometimes agree to perform a Supplemental Environmental Project, a tangible environmental or public health project that goes beyond what any law already requires. These are not penalty substitutes. Every settlement that includes one must still include a penalty that recoups the economic benefit the violator gained from noncompliance and retains real deterrent force.¹⁰ The project must have a direct connection to the violations being resolved, involving the same pollutant, the same health effects, or the same community harmed. The EPA cannot demand that a defendant perform one, and defendants cannot simply write a check to a charity. They have to actually carry the work out, though they can hire contractors to help.

Defenses and Liability Protections

Given how broadly CERCLA casts its net, defenses matter enormously. They fall into two groups: the original 1980 statutory defenses and the liability protections added by the 2002 Brownfields Amendments.

Original Statutory Defenses

CERCLA provides that a responsible party escapes liability only if it proves by a preponderance of the evidence that the contamination was caused solely by an act of God, an act of war, or the act or omission of an unrelated third party.² The word “solely” does the heavy lifting. If a hurricane damaged a chemical storage facility but shoddy maintenance contributed to the spill, the act of God defense fails. Courts define an act of God as an unanticipated grave natural disaster whose effects could not have been prevented by reasonable care. No reported federal court decision has ever sustained this defense successfully, largely because modern forecasting technology makes most natural events at least partially foreseeable.

The third-party defense requires showing that someone with no contractual relationship to the defendant caused the contamination, and that the defendant exercised due care with respect to the hazardous substances and took precautions against the third party’s foreseeable conduct. This defense is narrow. If a prior owner contaminated a site but you purchased the property from that owner, the contractual relationship created by the sale typically disqualifies you from using this defense on its own, which is exactly why Congress later created the innocent landowner protections.

Brownfields Liability Protections

The 2002 Small Business Liability Relief and Brownfields Revitalization Act created three new categories of protected parties, all tied to environmental due diligence before acquiring property.¹¹

Innocent landowners: buyers who conducted all appropriate inquiries before purchase and neither knew nor had reason to know of contamination. Inheritors and governments that acquire contaminated property through eminent domain or tax forfeiture also qualify.¹²
Bona fide prospective purchasers: buyers who knowingly acquire contaminated property but conducted all appropriate inquiries, are not affiliated with any responsible party, and do not interfere with ongoing cleanup or restoration work.
Contiguous property owners: owners whose land was contaminated solely by a release migrating from a neighboring property, who did not contribute to the contamination and conducted appropriate inquiry before purchase.

All three protections share core requirements. The party must conduct all appropriate inquiries before acquisition, exercise appropriate care regarding any known contamination, cooperate fully with cleanup authorities, comply with land use restrictions, and respond to government information requests. Dropping the ball on any ongoing obligation can strip the protection entirely.

Due Diligence as the Gateway to Protection

Because CERCLA liability follows the land, environmental due diligence before buying commercial or industrial real estate is the gateway to every liability protection the statute offers. The standard tool is a Phase I Environmental Site Assessment conducted under ASTM Standard E1527-21, which defines good commercial practice for identifying recognized environmental conditions on a property.¹³ The assessment reviews historical records, regulatory databases, and site conditions to flag potential contamination. It must be completed within one year before the acquisition date, with certain components updated within 180 days of closing.

A Phase I assessment for a commercial property typically costs between $1,500 and $6,000, depending on site size and complexity. If it turns up recognized environmental conditions, a Phase II assessment involving soil and groundwater sampling follows, at significantly higher cost. Without the assessment, a buyer cannot claim innocent landowner or bona fide prospective purchaser protection and could end up personally liable for contamination that predates the purchase by decades.

Pollution Legal Liability insurance offers another layer of protection, covering cleanup costs, third-party injury claims, and business interruption losses tied to both known and unknown contamination at a property. These policies can cover historical contamination already present at the time of purchase, which is precisely the risk gap that standard commercial general liability policies exclude. For buyers of older industrial properties, this insurance is often a condition of closing the deal.

Filing Deadlines

Filing deadlines vary by claim type, and missing them can permanently eliminate the right to recover costs worth millions.

Under CERCLA, cost recovery actions for removal actions (emergency or short-term cleanups) must be filed within three years after the removal action is completed. Cost recovery for remedial actions (long-term cleanups) must be filed within six years after physical on-site construction of the remedy begins. Contribution claims, where one responsible party seeks to recover a share of costs from other responsible parties, must be filed within three years of a final judgment in a cost recovery action or within three years of entry of a judicially approved settlement or qualifying administrative order.¹⁴

For Clean Water Act civil penalty claims, a five-year statute of limitations applies under the general federal limitations statute. Clean Air Act and Clean Water Act citizen suits target ongoing violations, so the practical question is often whether the violation is continuing rather than whether a clock has run. Even so, the 60-day pre-suit notice requirement functions as its own deadline trap. A citizen suit filed before the notice period expires gets dismissed regardless of the merits.

Settlement and Contribution Protection

Most Superfund enforcement actions end in negotiated settlements rather than trials. Settlements take two main forms. An administrative settlement agreement and order on consent is used for earlier-stage work like site investigations. A consent decree, which requires public comment and court approval, is the only settlement tool the EPA can use for the final remedial action phase of a Superfund cleanup.¹⁵ Settlement agreements typically include a detailed statement of work specifying the cleanup requirements, community involvement obligations, and reporting duties the responsible party must fulfill.

Settlement carries a powerful incentive: contribution protection. A party that resolves its liability with the government through an approved settlement cannot be sued for contribution by other responsible parties for the matters covered by the settlement.¹⁴ The settlement does not release the other responsible parties from their own liability, but it reduces what they collectively owe by the amount the settling party paid. For smaller contributors at a multi-party site, settling early and locking in contribution protection is often the most cost-effective strategy.

Federal Liens on Contaminated Property

When the government spends money cleaning up a site, CERCLA authorizes a federal lien on all real property belonging to the responsible party that is subject to or affected by the cleanup.² The lien attaches when the government first incurs response costs or when the responsible party receives written notice of potential liability, whichever comes later. It remains in place until the liability is satisfied or becomes unenforceable under the statute of limitations.

These liens can devastate property values and make contaminated land effectively unsaleable. The lien must be filed in the appropriate state or county office, and once recorded, it takes priority over most interests except those already perfected under state law before the filing. The government can also enforce the lien through an action in rem in federal district court, which targets the property itself rather than the owner personally. For bona fide prospective purchasers who take advantage of CERCLA’s liability protections, a separate windfall lien provision allows the government to recapture unrecovered response costs to the extent the cleanup increased the property’s fair market value.¹¹

1
eCFR. 40 CFR 19.4 – Statutory Civil Monetary Penalties, as Adjusted for Inflation, and Tables
2
Office of the Law Revision Counsel. 42 USC 9607 – Liability
3
Legal Information Institute. Comprehensive Environmental Response, Compensation and Liability Act (CERCLA)
4
United States Environmental Protection Agency. Superfund Liability
5
U.S. Environmental Protection Agency. Summary of the Clean Water Act
6
Office of the Law Revision Counsel. 42 USC 9601 – Definitions
7
Environmental Protection Agency. Natural Resource Damages: A Primer
8
Office of the Law Revision Counsel. 33 USC 1365 – Citizen Suits
9
Office of the Law Revision Counsel. 42 USC 7604 – Citizen Suits
10
U.S. Environmental Protection Agency. Supplemental Environmental Projects (SEPs)
11
U.S. Environmental Protection Agency. Summary of the Small Business Liability Relief and Brownfields Revitalization Act
12
Environmental Protection Agency. Third Party Defenses/Innocent Landowners
13
ASTM. E1527 Standard Practice for Environmental Site Assessments
14
Office of the Law Revision Counsel. 42 USC 9613 – Civil Proceedings
15
U.S. Environmental Protection Agency. Negotiating Superfund Settlements