Minimizing Liabilities Facing POTWs
Joseph M. Zorc, John C. Hall, Christopher L. Rissetto
Published in the January 1988 issue of the
Journal Water Pollution Control Federation. Download the original article here.
Hazardous waste issues are encountered in all facets of municipal services. Congressional directives to regulate hazardous wastes have primarily originated under three statutes: the Clean Water Act (CWA),1 the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA, also known as Superfund),2 and the Resource Conservation and Recovery Act (RCRA).3 Despite Congressional objectives to interrelate these laws, compliance with one or two of these statutes does not ensure compliance with the last.
Because of the expanding regulatory requirements and piecemeal implementation by government authorities, substantial exposure to liability may occur despite a municipality's good faith efforts to comply with applicable statutory and regulatory mandates. Difficulties in achieving compliance with hazardous waste rules are related to the extensive statutory provisions regulating such materials and the regulatory agendas for implementing new Congressional directives.

Interrelationships between the statutes exist and there are strategies that reduce exposure to liability (e.g., the Federally permitted release provision of the Clean Water Act, and CERCLA). Moreover, the legal ramifications of recent government initiatives that impose demands to control hazardous wastes entering or leaving publicly owned treatment works (POTW s) expose POTW s to certain liability: permit by rule procedures under RCRA, pretreatment program protections, sludge disposal rules, and whole effluent toxicity implications.

By effective statutory and regulatory coordination liability for releases of hazardous substances from POTWs can be limited.

Hazardous wastes may enter and exit a. POTW through a variety of ways. Most hazardous wastes reach a POTW by one of the following routes: industrial inputs to the sewer system; illegal dumping of hazardous waste; dedicated pipe, truck, or rail under POTW supervision; small quantity generator inputs (households); or generation at POTW/machinery operations from.

Depending on how a waste enters the system and how it leaves the system, different regulatory requirements apply. For example, industrial inputs are generally controlled under the pretreatment program of the Clean Water Act; however, depending upon the circumstances, regulation under CERCLA may also apply. Midnight dumping into a POTW may be subject to liability under the CWA, RCRA, and CERCLA. When an industry decides to transport its hazardous waste directly to a POTW, both the CWA and RCRA apply. When small quantity generators are involved, a combination of RCRA and CWA may be applicable. Lastly, a combination of RCRA and CERCLA apply to how a POTW generates its own wastes (such as used oil).

A different set of statutory requirements may apply to wastes leaving the facility. For example, all POTW discharges are covered by the CWA and in many instances
CERCLA. Sludge disposal can be regulated under CW A, RCRA, and CERCLA. Groundwater contamination from POTW operations is addressed primarily under RCRA or CERCLA. Air emissions that result from sludge incineration have the distinction of being regulated by four statutes: the Clean Air Act, CWA, RCRA, and CERCLA.
Because of the substantial coverage overlap, EPA generally decides to regulate a particular input route or release route under only one statute. However, the scope of the regulation under each Statute is not coextensive; therefore, problems that need to be addressed may go unresolved.


The Clean Water Act has several provisions that regulate hazardous substance discharge to POTWs. The primary mechanism for controlling discharges from a POTW is the (NPDES) permit program. The NPDES permit is the vehicle for identifying appropriate effluent limitations and allowable point sources where discharges may occur. Any discharge that is not in compliance with a NPDES permit requirements is unlawful. Conversely, the Act provides that the NPDES permit is a shield to liability for all circumstances identified and authorized through permit issuance.

All releases of wastes into a POTW must comply with the General Pretreatment Regulations. As stated in the regulations the purpose of the pretreatment program is to fulfill three objectives. First, to prevent the introduction of pollutants into POTWs will
Interfere with the operation of the POTW, including interference with the use or disposal of municipal sludge. Second, to prevent the introduction of pollutants into POTWs that will pass through the treatment works or be otherwise incompatible with such works. Third, to improve opportunities to recycle and reclaim municipal and industrial wastewater and sludges.

In addition to the general prohibition of interference or pass through, EPA has established several specific prohibitions on the introduction of pollutants that create a fire or explosion hazard, are excessively corrosive, may obstruct flow, are slug loads, or are excessively hot. Although categorical restrictions are established for certain types of indirect industrial discharges, such, as electroplaters, the basic framework of the pretreatment program relies heavily on each municipality identifying its own problems and proposing solutions. EPA promotes the development of local limits to account for site-specific factors that may concern the performance of a POTW or the disposal of its sludge.

Although the pretreatment program scope appears broad, several issues are not currently addressed such as exfiltration of toxics and potential groundwater contamination from sewer exfiltration or sludge disposal. EPA's removal credits provision was invalidated in
Natural Resources Defense Council, Inc., v. EPA, 790 F.2d289 (3rd Cir. 1986). On November 5, 1987, EPA included consideration of sewer exfiltration in determining industrial pretreatment requirements. As a result of the domestic sewage study, EPA's pretreatment program may undergo substantial revision.

The Clean Water Act is intended to regulate sludge disposal from treatment works. Before the 1987 CWA amendments, the scope of the section on sludge disposal was fairly narrow. Where a sludge disposal practice is likely to impact a navigable water, it is prohibited "except in accordance with an [NPDES] permit issued by the Administrator..." It should be noted that groundwater contamination from sludge application is not specifically covered by the section. The section also requires EPA to issue regulations governing the disposal of sludge; however, to date, EPA has provided little guidance on this issue. Based on recent EPA announcements, sludge disposal rules should be issued shortly that provide limitations on the amounts of hazardous substances that may be contained for a specific usage. Thus, for the past 15 years, since the adoption of the CWA, POTWs have been conducting sludge disposal without the benefit of regulatory guidelines for toxics.

In the Water Quality Act of 1987, which amended the Clean Water Act, Congress directed EPA to issue regulations to limit toxic pollutants in sludges that "may adversely affect public health or the environment." This effectively increased the scope of EPA's authority beyond the "navigable waters" consideration. The new amendments require EPA to control sludge disposal as Section 402 permits unless EPA permits sludge disposal under other federal statutes, such as RCRA Subtitle C, Hazardous Waste Management, or an approved state permit consistent with the 1987 amendments to the CWA. A key question regarding sludge disposal is whether remedial measures will be required where prior disposal was not protective of public health or the environment. Under RCRA such actions are the norm while under the CWA remedial measures are rarely required.


As a general matter, the vast majority of POTWs are not concerned about the applicability of RCRA to POTW influent because the statute exempts domestic wastewater from its jurisdiction. Although the statute language is fairly simple, EPA established a complex regulatory framework around this exclusion.

EPA's regulations establish a two-tiered approach in applying the domestic sewage exclusion. EPA defined sanitary waste as domestic waste, and based on the legislative history of the provision, included all industrial waste in the exclusion as long as it mixes with domestic sewage before entering the POTW property boundary headworks. However, unlike the sanitary waste exclusion, the exclusion for mixed sanitary and industrial waste applies when the mixture "passes through a sewer system to a publicly owned treatment works for treatment." According to EPA, "an industrial waste stream that never mixes with sanitary wastes in the sewer system prior to treatment or storage does not fall within the (exclusion)."

A central issue surrounding the domestic sewage exclusion is when it takes effect. EPA's interpretation is that the exclusion applies when a waste "first enters a sewer system that will mix it with sanitary wastes before storage or treatment by a POTW.” This means that the exclusion may apply before actual mixing of the waste with domestic sewage. The key to invoking the domestic sewage exclusion is ensuring that industrial wastes mix with sanitary waste outside the property boundary of the POTW.

For those municipal facilities that do not fall within the domestic sewage exclusion, permit-by-rule procedures, may apply.
6 The permit-by-rule is a RCRA regulation that deems certain facilities, which are permitted by other environmental programs, to be coveted by a RCRA permit if certain conditions are met. Those rules provide that a POTW that accepts hazardous waste for treatment is deemed to have a RCRA permit by-rule if the following conditions are met:
1. The POTW has an NPDES permit.

2. The POTW complies with the conditions of that permit.

3. The POTW complies with:
(i) 40 C F R Part 264.11 (identification number);
(ii) 40 C F R Part 264.71 (use of manifest system);
(iii) 40 C F R Part 264.72 (manifest discrepancies);
(iv) 40 C F R Part 264.73(a) and (b) (1) (operating record);
(v) 40 C F R Part 264.75 (biennial report);
(vi) 40 C F R Part 264.76 (unmanifested waste report);
(vii) for NPDES permits issued after November 8, 1984, 40 C F R Part 264.101 (corrective action for solid waste management units).

4. The waste meets all federal, state, and local pretreatment requirements that would be applicable to the waste if it waste as domestic waste, and based on were being discharged into the POTW through a sewer pipe or similar conveyance. The Identification and listing of Hazardous Waste regulations excludes from the definition of "solid waste," and, hence, from the definition of a hazardous waste, any mixture of domestic sewage and other wastes that passes through a sewer system to a POTW for treatment. Thus, the General Rules on Hazardous Waste Management provision the permit-by-rule effectively means that any POTW that accepts hazardous waste by rail, truck, or dedicated pipe (a pipe that does not mix such waste with domestic wastewater) is a RCRA-permitted treatment, storage, or disposal facility (TSDF) if it satisfies these conditions.

5. EPA currently estimates that there are 26 such POTWs. Additional POTWs may be subject to this provision if they accept CERCLA wastewaters. However, EPA recently published a guidance document on the applicability of RCRA to POTW s stating that if POTWs inadvertently accept hazardous wastes via truck, pipe, or rail, it becomes a RCRA facility and subject to permit-by-rule and may be subject to civil or criminal penalties.
EPA only regards conditions 1; 3(i); and, where applicable, 3(vii); as conditions precedent to the "issuance" of a permit-by-rule. Each of these conditions must be satisfied for the permit-by-rule to be "issued." The other conditions set forth in the regulation are considered to be conditions subsequent, or conditions that must be met as ongoing permit-by-rule requirements. This is extremely significant, for it means that a POTW's failure to comply with its NPDES permit constitutes a violation of both permits. To illustrate this point, if a POTW accepts hazardous waste on a day or during a week in which it has violated its NPDES permit for whatever reason, the POTW is not subject to liability for failure to have a TSDF permit. Rather, the POTW is held to have violated its NPDES permit and its RCRA permit-by-rule. Hence, the POTW may be subject to enforcement under both the Clean Water Act and RCRA. Similarly, if the hazardous waste fails to meet all federal, state, or local' pretreatment requirements that would be applicable if the domestic sewage exclusion applied to the waste, at a minimum, the POTW is held to have violated its permit-by-rule and may have violated both permits, If the POTW is not in compliance with any of the RCRA requirements that operate as conditions subsequent, the POTW is held to have violated its RCRA permit only.

Perhaps the most significant condition listed in the permit-by-rule provisions is the one pertaining to corrosive action. The corrective action regulation provides that a facility seeking a permit for the treatment, storage, or disposal of hazardous waste must institute corrective action as necessary to protect human health and the environment for all releases of hazardous waste or constituents from any solid waste management unit (SWMU) at the facility, regardless of the time at which waste was placed in such a unit. It should be stressed that corrective action under this provision will address releases of hazardous waste
and solid waste containing hazardous constituents. Currently, there are approximately 375 such constituents listed by EPA.7 Furthermore, recently released EPA guidance for implementing RCRA permit-by-rule requirements at POTWs indicates that POTW units such as sedimentation tanks, aeration tanks, wastewater treatment ponds, trickling filters, aeration basins, and other units used for treatment, storage, or disposal of solid waste will be considered SWMUs for the purposes of corrective action.


Sludge generated by a POTW is defined as a solid waste and, therefore, technically, is also regulated under RCRA. EPA, in implementing RCRA, had initially determined that sludge from POTWs was best regulated under the CW A. This position made sense because RCRA Section 1006 advised EPA that, where a solid waste was adequately regulated under another federal statute, duplication of regulation was to be avoided. However, since that time, EPA has indicated that sludge regulation may be subject to RCRA requirements.

Because of EPA's slow development of sludge disposal regulations and concerns that adequate safeguards were not being provided for disposal of sludges, Congress amended RCRA pursuant to the Hazardous and Solid Waste Amendments of 1984. In particular, Congress was concerned that the domestic sewage exclusion provided an inference that sludges did not pose a health threat because they were not considered hazardous waste subject to Subtitle C or RCRA unless they failed a characteristic test (for example extracting procedure (EP) toxicity) or were specifically listed as a hazardous waste. Despite
· their innocuous designation, health risks were present because most, if not all, municipal sludges will contain listed hazardous wastes. Under RCRA Congress required EPA to conduct a detailed evaluation of the domestic wastewater exclusion and hazards posed by sludge disposal. EPA was also required to analyze the impact of wastewater lagoons on groundwater contamination. Based on the outcome of these studies, EPA is required to promulgate regulations either under RCRA, or the CWA, EPA's pretreatment rule making authority. On August 22, 1986, EPA issued an advanced notice of proposed rulemaking to initiate the rulemaking process based on the domestic sewage study findings.

Based on the study results, EPA has again decided not to list POTW sludge as hazardous waste but to regulate it under the CWA. This decision essentially eliminates RCRA jurisdiction of POTW's sludge disposal (except possibly for those sludges that fail a characteristic test). However final rulemaking must be completed.


The comprehensive environmental response, compensation and liability act of 1980 (Superfund) (CERCLA) was passed by Congress to serve as a catch-all mechanism by which prior disposal of hazardous substances, which now pose a public health or environmental threat, may be addressed. The retroactive nature of this statute and the broad interpretation of its reach poses the most substantial basis for municipal hazardous waste liability.

Liability attaches under CERCLA whenever there is a release of hazardous substance that poses a threat to public health, welfare, or the environment. EPA takes a very broad view of applicability of CERCLA because
· Congress used the term hazardous substance rather than hazardous waste in establishing the parameter covered by the statute. Thus, even if EPA has not listed a particular substance such as municipal sludge as a hazardous waste under RCRA because of other listed hazardous substances present in the sludge, CERCLA liability may attach where prior sludge disposal may pose a threat.

CERCLA liability may also attach for discharges from POTWs unless it is a "federally permitted release" as defined under Section 101(10):
'federally permitted release' means (A) discharges in compliance with a permit under section 402 of the Federal Water Pollution Control Act, (B) discharges resulting from circumstances identified and reviewed and made part of the public record with respect to a permit issued or modified under section 402 of the Federal Water Pollution Control Act and subject to a condition of such permit, (C) continuous or anticipated intermittent discharges from a point source, identified in a permit or permit application under section 402 of the Federal Water Pollution Control Act, which are caused by events occurring within the scope of relevant operating or treatment systems ... (J) the introduction of any pollutant into a publicly owned treatment works when such pollutant is specified in and in compliance with applicable pretreatment standards or section 307(b) or (c) of the Clean Water Act and enforceable requirements in a pretreatment program submitted by a State or municipality for Federal approval under section 402 of such Act ...
The key to a POTW perfecting compliance with the federally permit releases lies in the NPDES permitting process and compliance with NPDES terms and conditions. Only those charge points identified in the issuance process qualify for this protection.

POTW must also be sure to enumerate and identify the conditions under which various discharges may occur to ensure that the discharge is allowable under the permit (an upset condition, for instance). Expected operational events, such as a 1 to 5% violation of a permit should also be identified to ensure that violations are not classified as unpermitted releases. Lastly, all possible hazardous substance not identified is not a federally permitted release.

For those events, such as slug loading, midnight dumping of toxic substances that are not allowed under any NPDES permits, the innocent third party defense allow under CERCLA may apply. A cautionary note is that the provision in Section 107 is narrowly construed. Reporting of such events as required by CERCLA and follow-up investigation under pretreatment authority would be highly persuasive evidence that such activities are not condoned by POTW.


Although the regulatory program’s toxic substance control appears comprehensive, POTWs are, nonetheless, open to substantial liability for accepting and treating hazardous wastes from industrial and domestic sources. Liability may attach despite full compliance with RCM and the CWA. Liability arises most frequently under CERCLA because it was designed to address the release of hazardous substances that are not explicitly regulated under other statutes. The primary reasons for this liability exposure are that all releases of hazardous substances are not addressed or permitted by EPA, and the regulatory overlap is incomplete in certain areas such as pretreatment program and sludge disposal. The major areas where apparent regulatory compliance with the CWA or RCM may, nonetheless, lead to liability under CERCLA are: sludge disposal, effluent discharge, exfiltration from sewers, and groundwater contamination (for example, lagoons).


EPA has made a basic decision not' to address hazardous substances in domestic sewage under RCRA. This decision was supported by Congress's direction to provide an exemption for domestic sewage under RCRA as stated in the preamble to the RCRA regulations establishing the domestic sewage exemption:
The exclusion of domestic sewage and mixtures that pass through sewer systems to POTW's is based on Congressional intent, not an Agency determination about the relative health and environmental risks presented by such waste streams. The Agency acknowledges that some mixtures of domestic sewage with other wastes may present environmental risks and that some non-domestic wastes may have properties similar to these of exempted domestic wastes. In response EPA can only assume that such factors were not determinative in the Congress's creation of the exclusion.
However, sludge disposal is not covered under the domestic sewage exemption and is expressly included in the definition of solid waste. EPA may, in its regulatory authority, determine that POTW sludges are best regulated under the CWA rather than RCRA. Unfortunately the primary mechanism for insuring safe sludge disposal, the pretreatment program, is not coextensive with RCM. The pretreatment program normally only addresses 125 toxic pollutants whereas RCM addresses over 400. RCM also applies hazardous waste characteristic tests (such as EP toxicity) that are not applied to sludge disposal under the CWA.

The primary mechanism for assuming safe sludge disposal was the development of local limits based on sludge disposal criteria. Unfortunately, such criteria have not been published. Therefore, POTWs do not know if the current disposal practices are environmentally safe or sufficiently protective of public health. In the disposal of solid and hazardous waste mixtures, RCRA is directly concerned with groundwater impacts in addition to other public health factors. The pretreatment program does not address this factor. EPA recently decided to suspend rulemaking on sludge disposal criteria as a result of a D.C. Circuit Court of Appeals case stating that air quality standards must be health-based and not a function of the implementation cost.

Regulation of POTW sludge disposal practices has been left to the state/local decision-making process and are, in the federal sense, unpermitted. This approach was, to a large extent, consistent with the CWA. Under RCRA, some form of permitting under Subtitle C or delisting procedure would have been required to allow sludge disposal because of the mixture rule. As previously stated, Congress no longer agrees with EPA's regulatory approach and is requiring sludge disposal permits either under the CWA, RCM Subtitle C, or other equivalent mechanism.

Lagoons, which often fill with sludge that may be contaminated by toxic substances, were generally not reviewed under the CWA for groundwater impacts other than from conventional pollutants. Few, if any, NPDES permits addressed this route of hazardous waste release. Under RCM or CERCLA, contaminated sludge disposal normally requires some form of corrective action where groundwater impacts may be identified. However, under the CWA EPA was not addressing the impacts of this sludge disposal, whereas other statutes would have. Congress, unhappy with EPA's approach, has mandated that EPA investigate this hazardous substance release route.


The NPDES permit program is intended to provide comprehensive protection from adverse effects of effluent discharges on the Nation's waters. Limitations on this program's ability to provide full coverage stems from a lack of standards for determining effluent limitations. This is similar to the problem associated with determining appropriate sludge contaminant levels under the pretreatment program. Where standards do not exist, contaminants are unpermitted and may be unregulated.

As a surrogate toxicity measure for the many toxic pollutants received at a POTW, EPA is beginning to require using a whole effluent toxicity test. This test is somewhat analogous to' the RCM characteristic tests used to classify a waste as hazardous. The bioassay test secured further support under the 1987 CWA amendments that dealt with stat; adoption of toxic water quality standards.

Where test results are positive, the whole effluent toxicity test provides the inference that additional pretreatment
is required because unacceptable pass through of toxic pollutants is occurring, and the effluent violates the free-from criteria contained in virtually all NPDES permits-no toxic discharge in toxic amounts. The important issue that this raises is that while individual pollutant levels may be acceptable on an individual effluent limitation basis, the Sum of those pollutant discharges may not be acceptable. Because the POTW is responsible for allowing the appropriate introduction of toxic pollutants into the sewer system, the POTW is likewise responsible to ensure that the cumulative affects of the discharge also do not pose either public health or environmental threats, regardless of the existing permit limitations.


Exfiltration of hazardous wastes before treatment at a POTW is an issue that has received little, if any, attention from EPA. For example, EPA, generally, has not required that detailed evaluation or permitting of combined sewer overflows (CSO), which many have recognized as a major avenue for release of toxic pollutants into the environment. As a result, the environmental and public health impacts of CSO are not fully known nor has the agency formally condoned such activities. A formal analysis of CSO effects on receiving waters is not required, and EPA has had a shifting policy concerning whether CSOs need to be considered at all in evaluating pretreatment requirements.

The federal pretreatment program in 1978 required the POTW to account for CSO discharges in, allowing the introduction of toxic pollutants into the sewage system and in calculating removal credits.8 This provision was relaxed by EPA in 1981 and dropped completely from the regulations in 1984.9 The Natural Resources Defense Council (NRDC) challenged EPA's refusal to account for CSO releases under the pretreatment rules and overturned the Agency's position in 1986. The court found that EPA may not ignore the adverse impact of CSOs in regulatory industrial inputs to the sewer system even though EPA claimed that it would only cause a 7.3% increase in toxic pollutants discharged on the average, a value EPA considered inconsequential. Thus, EPA is redrafting the removal credits regulation to account for CSO r losses.

Because of these changing positions and regulatory malaise regarding CSO discharges there is little, if any, regulatory basis for stating that CSO discharges are authorized under the CWA. Perhaps the most important feature of the Court’s decision in
NRDC v. EPA was to recognize that:
The impact of a large combined sewer overflow event on any viable aquatic biota element in the receiving water can be extremely detrimental ...
(a) combined sewer overflow is a major environmental hazard, and has been viewed as such not only by EPA, but by Congress as well.
Given that the potential adverse impacts of CSOs are so widely recognized, a POTW s failure to regulate releases, even though EPA has not required regulation, may be viewed dimly. The 4th Circuit Court found the local sewer authority liable for the downstream impacts of certain pollutants in its discharge even though the permit contained no restrictions on those pollutants.10


In evaluating potential liability associated with issues identified above, the focus of the analysis primarily concerns CERCLA. For the most part, additional requirements under the CW A may not be avoided where a threat is identified (for example, failure of whole effluent toxicity test); or would one expect a permit to limit future' actions. As previously explained, the NPDES permit shields one from liability under the CWA for discharge consistent with the permit. This does not mean that liability does not exist for past actions under other federal statutes, particularly CERCLA. Defenses to CERCLA liability are narrowly fashioned. The federally permitted release exception provides the best basis for avoiding liability occurring pursuant to the operation of a POTW. However, as the following evaluation will show, the application of this section is extremely limited because of inconsistencies among the regulatory programs and loopholes in coverage.


Because most past sludge disposal was not done pursuant to an NPDES permit, it will not be subject to the release, provision. Thus, CERCLA Section 101(10)(B) is inapplicable because no NPDES permit addresses sludge requirements. In those instances where sludge disposal practices may have been discussed during the NPDES issuance process and even made a condition of the permit, it is likely that the specific hazardous substances and form of release were not mentioned or evaluated. Because the nature, of the hazardous substance release was not identified and approved as sludge, per se) this protection will not attach. CERCLA Section 101(10)J is equally unavailable (the pretreatment exception) because the specific pollutant must be identified under the pretreatment program. Because EPA has not even published the sludge use regulations so that POTW can evaluate the specific hazardous pollutants it is rather difficult to be in compliance with allowable pollutant release levels.

The most significant concern on sludge disposal is that EPA will (if not must) require that corrective action be taken to bring past sludge disposal measures up to present standards. Depending on the authority used to require such action, (RCM CERCLA, or the CWA) the response action and cost could be drastically different.

As stated earlier, liability under RCRA for POTW effluent discharges is limited because of the domestic sewage exclusion and RCRA language on avoiding duplicative regulation and enforcement. Assuming that the facility is not covered by the permit-by-rul
e procedures, RCRA is essentially not applicable to TSDF activities. However, CERCLA may apply to require corrective action to the hazardous substance threats caused by point source discharges. There are four provisions of CERCLA that shield a discharge from liability; however, the liability shield is only applicable to those hazardous substances that are identified as part of the public record, and are subject to permit conditions. Therefore, the failure to fully analyze all hazardous substances in the effluent and obtain federal approval for the discharge levels means that CERCLA liability may attach if any previously unpermitted constituents are later determined to pose a threat to public health, welfare, or the environment.

Under CERCLA Section 101(10) (C), plant upsets and CSO discharges may be included under the liability shield if they are identified in the permit, and are in the scope of expected conditions. Again, the key is disclosing all such relevant operational occurrences and potential point sources during the permit application process. Protection is not afforded those who fail to make full disclosures.

An alternative vehicle for obtaining the federally permitted release protection for discharges is through the pretreatment program as specified in Section 101(10)(J). The discharge or pass through of the pollutant must be acceptable fur EPA to approve the industrial input to the sewer system. Pollutant discharges into a POTW receive the protection where the pollutant is specifically identified and the discharge is in accordance with all federal pretreatment rules. Where an industrial discharge is not in accordance with pretreatment requirements or fails to specify all pollutants of concern, the industrial user is clearly liable fur the impacts of such release. Arguably the POTW is also because it agreed to accept the waste for treatment. A possible defense to liability for the POTW exists in CERCLA, which is the innocent third party defense. To perfect this defense the POTW must demonstrate that the release was caused solely by the act or omission of a third party (the industrial user), the POTW had exercised due care in addressing the release, and precautions were taken against foreseeable acts.

In essence, the provision argues for stringent pretreatment enforcement to avoid liability for accepting slug loads or allowing interference or pass through. Where a POTW allows an industrial user to repeatedly violate its pretreatment obligations, that defense will be lost for that industry.


Most NPDES permits contain "free from" language based on state narrative water quality standards. Because of this language, any violation of a whole effluent toxicity test gives rise to the presumption that the hazardous substance mixture in the effluent are violating the "free from" requirements and the NPDES permit. Arguably, this is also a violation of toxic and pretreatment provision of the CWA because unacceptable pass through of toxic pollutants is likely occurring. Given these inferences, it is probable that EPA would argue that the federally permitted release provision is unavailable, even if no one hazardous substance violated the NPDES conditions. Under such circumstances, the POTW would be well advised to initiate an immediate investigation to determine the source of the problem. If no source(s) could be pinpointed, a general reduction in toxic loadings to the facility may be warranted.

Alternatively, should such testing yield negative results, the POIW would argue that the protections of the federally permitted release section should apply because EPA's accepted measure of general toxicity does not indicate any need for further toxic reduction and the effluent has a clean bill of health. Under such circumstances, the full protection of the federally permitted release clause should apply.


One particular problem facing all POTWs is the possibility of explained and unapproved releases of hazardous substances to the sewer system, commonly known as midnight dumping. Such practices constitute major violations of the CWA and RCRA. Therefore, the federally permitted release protection will dearly not apply.

Similar to the pretreatment violation scenario, a defense for CERCLA liability associated with the release is available under the innocent third party definition of that statute. However, where such releases occur, EPA is required to receive notification pursuant to CERCLA and NPDES permit conditions. After such notification is provided, however, the POTWs duties are not over. Actions need to be taken to limit the release impacts 'and, where appropriate, separately dispose of the waste under RCRA.

Reimbursement for costs associated with remedying the release is available under CERCLA but preauthorization of action is required. Lastly, it would be prudent to contact EPA regarding the status of any sludge that may have become contaminated because of the release to determine whether secure disposal of that residual is necessary.


Despite the uncertainty over safe levels of hazardous substances found in POTW sewage, discharges, and sludge, steps may be taken to limit liability for corrective measures to address past releases.

  • Avoid RCRA permit-by-rule. Where possible, RCRA jurisdiction should be avoided because of the complexity of achieving compliance under both RCRA and CWA continuously. (Receipt of CERCLA wastes may trigger this condition,) RCRA corrective action requirements for solid waste management units could be extremely expensive to comply with and lead to operational difficulties at the POTW. At a minimum, costly groundwater monitoring may be required to determine if there is a release of concern. Sludge disposal may be more difficult and substantially increase operation expenditures. If the POTW intends on accepting a RCRA CERCLA waste by dedicated pipe, truck, or rail, substantial precautions should be taken to ensure that no violations of applicable requirements will result. An NPDES permit modification should be sought to obtain permitted release protection and indemnification should be obtained for any future corrective actions caused by acceptance of waste.
  • Analyze all hazardous wastes in the influent/effluent and sludge. Federally permitted release protection under CERCLA is not available unless the potential release of the substance is identified during the NPDES permitting process. The POIW should also accept a continuing monitoring provision and inform EPA of any significant change in wastewater characteristics.
  • Should EPA require whole effluent toxicity resting, an agreement should be reached on the ramifications of either positive or negative results of such testing. This will help to establish that the combination of hazardous substances do not pose a threat and the discharge is acceptable to EPA.
  • Identity all point source discharges. Where system overflows or exfiltration may result in discharges, the POIW should ensure that all such point sources are identified in the permit application. The permit application should also explain the conditions under which such discharges are anticipated to occur (upsets, high flows, and so on).
  • Stringently enforce pretreatment programs. To ensure that the innocent third party defense is available in the event of illegal discharges to the sewer system, the POIW should stringently enforce all pretreatment requirements. Documentation of efforts to discover and prevent future occurrences is needed to meet the requirement of preventing foreseeable releases. Pretreatment regulations for the POIW should not allow the discharge of any pollutant not identified by the industrial user. Severe civil or criminal penalties should be adopted. This will aid in establishing the innocent third part defense in the event that a previously undisclosed waste is released to the plant.
  • Provide EPA notice of hazardous slug loads. Where slug loads of unauthorized hazardous wastes occur, notify EPA pursuant to CERCLA Section 103 and NPDES authorities. Do not presume that the two different program offices will confer with each other. Seek EPA advice on appropriate measures for secure disposal of the waste, including the sludge residual, if any.
  • Obtain sludge disposal permit. The surest vehicle for obtaining federally permitted release protection for sludge disposal is to obtain approval of the sludge disposal methodology in the NPDES permit. Under the 1987 CWA amendments, some form of sludge disposal permitting will be mandatory. Ensure that all hazardous substances in the sludge are identified during the permitting process. EPA must approve the disposal methodology with knowledge of the containment levels and application rates.
1. Federal Water Pollution Control Act, as amended, 33 U.S.c. 1251, et seq.
2. Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended by the Superfund Amendments and Reauthorization Act of 1986; 42 U.S.G. 9601, et seq.
3. Resource Conservation and Recovery Act of 1976, as amended by Hazardous and Solid Waste Amendments of 1984; 42 U.S.C. 6901., et seq.
4. U.S. Environ. Prot. Agency, “General pretreatment regulations for existing and new sources." Code of Fed. Regul., Title 40 Part 403,9 (1986).
5. U.S. Environ. Prot. Agency, "Part 261- Identification and listings of hazardous waste."
Fed. Regist., 45, 33097 (1980).
6. U.S. Environ. Prot~ Agency, "Administered permit programs: the hazardous waste permit program" Code of
Fed. Regul. Title 40 Part 270 (1986).
7. U.S. Environ, Prot. Agency, "Identification and listing of hazardous waste." Code of
Fed. Regul, Title 40 Part 261, 359 (1986),
8. U.S. Environ, Prot. Agency, "General pretreatment regulations for existing and new sources;'
Fed. Regist., 43,27765 (1978).
9. U.S. Environ. Prot, Agency, "General pretreatment regulations for existing and new sources."
Fed. Regist., 49, 31330 (1984).
Stoddard v. Western Carolina Regianal Sewer Authority, 784 F. 2d 120, 4th Cir. (1986).
Joseph M. Zorc, John C. Hall, Christopher L. Rissetto
Published in the January 1988 issue of the
Journal Water Pollution Control Federation. Download the original article here.