1. Overview and PRC Recommendations
2. Lower Passaic River: A Brief History of Development
3. Contamination of the Lower Passaic River
4. The USEPA Proposal
5. Project Design (River Miles 0 to 8.3)
6. The Current Status of the Lower Passaic River
7. Passaic River Coalition Recommendations (RM 8.3 to Dundee Dam)
8. Treatment Technology Options
9. Cited Materials

Overview and PRC Recommendations

One legacy of extensive industrial development along the Passaic River from Paterson to Newark Bay is the extensive pollution of water quality and sediments in the Lower Passaic River from Dundee Dam (between Garfield and Clifton) to the Bay, threatening public health and damaging aquatic ecosystems.

One of the major pollutant sources was the Diamond Alkali Company, known as the Diamond Shamrock Chemicals Company, which operated a pesticide manufacturing plant along the Passaic River in Newark. The company illegally dumped manufacturing byproducts (especially dioxin) from a Vietnam War defoliant, Agent Orange, into the river. Testing of the site and river in 1983 revealed high levels of dioxin, resulting in closure and capping of the site and federal designation of the Lower Passaic River as a Superfund site in 1984, known as the Diamond Alkali Superfund site, which has two study areas for the Lower Passaic and the Newark Bay. Ownership of Diamond Alkali has since passed to Occidental Chemical Corp (OxyChem). Forty years later, only the factory site capping and two “hot spot” dredging projects have been completed. All other efforts have involved monitoring, planning, project design, USEPA decisions, and legal efforts to minimize federal cleanup costs by placing the burden on the potentially responsible parties.

The dioxin issue is complicated by the existence of many other contaminants in the water and sediments, with over 100 industrial facilities identified as “potentially responsible parties”, all of which face liability for cleanup cases. Apportioning liability is both a technical and legal quandary. The U.S. Environmental Protection Agency approved a cleanup plan for the lower reach in 2016, from Mile 0 (at Newark Bay) to Mile 8.3, with an estimated cost of $1.38 billion. This plan involves partial dredging and removal of sediments, followed by capping of remaining materials in the river and long-term controls over future modifications to the river banks and bottom. Complete dredging of contaminants was rejected.

OxyChem was required by USEPA to design the cleanup plan for the upper nine miles. The interim remedial plan for the upper reach to Dundee Dam was approved by USEPA in 2021; it may require an addition $0.5 billion or so for removal of “hot spots” of contamination in this less-damaged area. Finally, OxyChem is required to complete a comprehensive study of related contamination in Newark Bay.

The Passaic River Coalition is and has been an active member of the Community Advisory Group (CAG) throughout the Superfund process. Most recently, in 2021, the Passaic River Coalition submitted comments to USEPA on the upper reach design (Dundee Dam to River Mile 8.3), including:

• The PRC believes that success of the proposed interim action of the Lower Passaic River would be significantly constrained by high water velocity during flood periods and intense weather events.
• The high water velocity would also cause higher dispersion of sediments during dredging.
• Also, the proposed interim action of the Lower Passaic River would harm fish migration.
• The USEPA decided not to cover the proposed cap with a geomembrane, hence low density activated carbon will be lost over time due to buoyancy.
• In addition, USEPA has yet to identify a dewatering facility site that is not in a flood zone and does not have an impact on Environmental Justice (EJ) Communities.
• USEPA has not identified a final disposal facility for the dewatered sediments. This site should be fully secure against climate change and should not fail as those did in Tennessee and South Carolina during high intensity storms. Also, this site should not be located in, near or affecting Environmental Justice (EJ) Communities.
• The proposed secure disposal of those contaminated sediments means if compromised those contaminants remain a health risk for current and future generations.

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Lower Passaic River: A Brief History of Development 

The Passaic River itself is approximately 129 kilometers long and starts near Mendham, NJ. The Passaic River basin drains roughly 935 square miles (almost 2,435 square kilometers) in northeastern New Jersey and southeastern New York. (See Passaic River Basin in Maps for more information about the Basin.)

The lower portion of the Passaic River below Dundee Dam drains to Newark Bay and is part of the New York-New Jersey Harbor estuary. The river is tidal up to the base of Dundee Dam, and with sea level rise the high-tide levels will increase. It was once a rich ecosystem inhabited by a diverse and abundant community of invertebrates and vertebrates with wetlands and tidal-creek habitats creating one highly diverse biological environment. Newark Bay was once a common place for oyster reefs, a profitable fishery in the 1800s. The estuary provided jobs for thousands and food for many. 

The industrial history of the Lower Passaic began early in the history of the United States of America. The industrial area of Paterson was created at the Great Falls from the late 1700s on as the nation’s first planned industrial development. The Dundee Dam, Canal and Lake were built in the early to mid-1800s for hydropower. The development of the river as a water supply and hydropower source, transportation center and a port during the Civil War encouraged the use of the river and led to dredging of the tidal river to enhance transportation. After the Civil War, the industrialization of Newark and Paterson increased, creating additional industries closer to the Passaic River. In the decades that followed, factories sprang up along the Lower Passaic River and drew power for their manufacturing operations from the Dundee Dam. No wastewater system collected sewage and industrial wastes to avoid water pollution. 

According to the 1939 Census, the Lower Passaic was a heavily industrialized area with over 2,900 manufacturing establishments in the watershed. The principal manufacturing centers were Paterson, Passaic, Clifton, Bloomfield, Garfield, Kearny, and Newark. The major industries were engaged in dyeing and finishing of textiles, the manufacture of wearing apparel, food and kindred products, and the production of textile machinery, chemicals, paints and varnishes, electrical equipment, and leather goods.

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Contamination of the
Lower Passaic River 

Industrial waste disposal, industrial sewage, combined sewer overflows and toxic chemical spills have greatly contaminated the Passaic River and Newark Bay including water and sediments. Most of the lower Passaic River was not dredged after the 1950s due to concerns about dumping sites for the dredged materials from the lower river. An historical review of water quality and sediment quality data reveals the significant presence of wide ranges of toxic chemicals throughout the lower Passaic River, whose concentrations greatly exceed allowable sediment quality benchmarks and probable ecological stressors. In 1970, the USEPA declared the Passaic River as the second most polluted river in America (Passaic River Basin, n.d.) and the New Jersey Legislature took notice in 1971, calling it “one of the ten most polluted rivers in the country” (CAPI, 1972).

From 1951 to 1969, the Diamond Alkali Company, known as the Diamond Shamrock Chemicals Company, operated a pesticide manufacturing plant at 80 Lister Avenue in Newark, on the banks of the Passaic River. The early last century marked the beginning of manufacturing operations, including the production of Dichlorodiphenyltrichloroethane (DDT) and phenoxy herbicides. Between 1951 and 1969, the Diamond Alkali Company operated a chemical plant that manufactured the herbicides 2,4,5- trichlorophenoxyacetic acid (2,4,5-T), chlorophenoxy acid and 2,4-dichlorophenoxyacetic acid (2,4-D). The compound 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), commonly referred to as dioxin, was produced as a by-product of the herbicide production process; the U.S. Environmental Protection Agency (USEPA) categorizes dioxin as a likely carcinogen. 

Subsequent owners used the property until 1983, when sampling at the site and in the Passaic River revealed high levels of dioxin. In 1983, hazardous levels of dioxins were identified during an investigation at the Diamond Alkali Company site. The production of Agent Orange (a defoliant) during the Vietnam War and the dumping and leakage of byproducts such as dioxins to the Passaic River were key detrimental incidents to the river environment. The Division of Science, Research and Technology of the New Jersey Department of Environmental Protection investigated the polluted chemical plant site and found 1.2 ppm of 2,3,7,8-TCDD. In 1984, USEPA added the Lower Passaic River (Newark Bay to Dundee Dam) to the National Priorities List, making the Passaic River eligible for cleanup funds under the Superfund program. The major contributors of pollution to the Superfund Site (either directly or as successor corporations) include Glenn Springs Holdings, Occidental Chemicals (Oxychem), Maxis Energy of Texas and others.

Though the manufacturing site itself was quickly capped, high dioxin levels were found in crabs and shellfish of Newark Bay. Dioxin concentrations in fish and crabs in the Passaic River are among the highest reported in any known scientific literature and are considered unsafe for human consumption. Fish and aquatic life are often better indicators of toxic contamination than sediments or water due to their propensity for the bioaccumulation of chemicals. Elevated levels of contaminants in the water and sediments may not be detectable, hence fish and aquatic life are always a better indicator of the degradation of the ecosystem due to contamination. 

The New Jersey Appellate Court in 1992 concluded that Diamond Alkali’s waste disposal policy essentially amounted to dumping everything into the Passaic River with full awareness of their inevitable migration to and devastating impact upon the environment. Toxic substances on the land were sequestered under the highly contaminated thick concrete cap 20 years ago, but the company had dumped dioxin into the Passaic River for decades. Dioxin transformed the river bottom into the toxic sludge which is popularly known as ‘Black Mayonnaise.’

In addition to Diamond Alkali, over 100 industrial facilities have been identified as potentially responsible for discharging a range of contaminants into the river, including polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), polychlorinated biphenyl (PCB) mixtures, polyaromatic hydrocarbons (PAH) compounds, Dichlorodiphenyltrichloroethane (DDT), and other pesticides. The contaminants are not limited to organic compounds; mercury, lead, and other metals are found in the river sediments. About 70 potential responsible parties (PRPs) have formed the Cooperating Parties Group (CPG) and signed an agreement with the USEPA to perform a remedial investigation/feasibility study plan for the Lower Passaic River Study Area Cooperating Parties Group under USEPA. 

Despite some interim dredging by the USEPA 40 years ago, the wastes are still there in the river.

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The USEPA Proposal

The USEPA got involved to address the contamination of the Passaic River due to its mandate to protect and safeguard the environment, public health, and natural resources in the United States. The contamination of the Passaic River was a result of historical industrial activities and the discharge of various pollutants, including toxic chemicals and heavy metals, into the river over many decades. The following is brief overview of the USEPA involvement:

• Environmental Concerns: The contamination of the Passaic River had been a concern for many years due to its adverse impacts on the environment, aquatic life, and the health of people living near the river.
• Public Awareness: The local communities and environmental groups in the Passaic River basin, including the Passaic River Coalition, raised awareness about the pollution and its consequences. They called for government action to address the issue.
• Legal Framework: The USEPA operates under various federal environmental laws, including the Clean Water Act and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), otherwise known as Superfund for its initial funding source. These laws empower the agency to act against pollution and hazardous waste sites.
• Designation as a Superfund Site: In 1984, the USEPA designated a portion of the Passaic River as a Superfund site, specifically the Diamond Alkali Superfund Site in Newark, New Jersey. The tidal river was included in the designation because contaminants came not only from Diamond Alkali but also other facilities, and tidal action has distributed the contaminants widely from Newark Bay to the Dundee Dam. This designation allowed the USEPA to take more direct action in investigating and cleaning up the contaminated areas, directly or through actions and payments of the potentially responsible parties.
• Investigation and Cleanup: The USEPA conducted and required others to conduct extensive investigations to assess the extent and nature of the contamination. These investigations included sediment sampling, ecological risk assessments, and human health risk assessments. The agency also worked to identify potentially responsible parties that could be held accountable for the pollution.
• Legal Action: The USEPA pursued legal actions and negotiations with potentially responsible parties to fund and conduct the cleanup efforts. This included corporations that had discharged toxic substances into the river.
• Remediation Efforts: The USEPA has been overseeing and implementing various remediation efforts to clean up the Passaic River, including dredging contaminated sediments, capping, and habitat restoration.
• Ongoing Involvement: The cleanup of the Passaic River is a long-term process, and the USEPA continues to be involved in monitoring and managing the environmental restoration efforts.

Figure 1 Lower Passaic River Cleanup Action plan

The contamination of the Passaic River is a complex and challenging environmental issue, and the USEPA’s involvement is part of its broader mission to protect the environment and public health through the enforcement of environmental laws and regulations. The USEPA expect one or more responsible parties include (Glenn Spring Holdings, Occidental Chemicals (OxyChem), Maxis Energy of Texas and others) to pay for most of the cleanup. Additional parties have contributed to investigation, design and remedial actions. In late 2022, USEPA and the Department of Justice announced a consent decree where 85 potentially responsible parties would pay $150 million toward the Lower Passaic River cleanup (both reaches). This settlement is separate from other legal actions such as with OxyChem and Maxis.

USEPA has selected a remedial design for the first 8.3 miles from Newark Bay upstream, including dredging of contaminated sediments (though not all sediments), and capping the river bottom bank to bank using clean sand for miles to avoid migration of remaining contaminants. Dredging the lower 8.3 miles stretch (up to 3.5 million cubic yards) and capping 7.5 acres of river bottom could take 6 to 8 years and cost $1.38 billion. The project as of early 2024 is in detailed design stage and implementation has not begun. 

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Project Design
(River Miles 0 to 8.3)

The USEPA $1.38B remediation plan includes bank to bank dredging and capping. Capping of the dredged riverbed consists of covering the dredged riverbed with a mixture of sand and activated carbon. The sand and carbon will be overlaid with a geotextile membrane finishing the capping. Sediments in the tidal portion of the river will be dredged to a depth of 2.5 feet (0.762 meters), except for the 3.22 km (1.7 miles) navigation channel closest to Newark Bay, where dredging will occur to greater depths. The dredged area will be capped without causing any additional flooding of the adjacent lowlands. The dredged sediment removal would involve mechanical dredging (bucket dredging), transporting the sediments to a processing facility for dewatering, transporting the processed dredged material for further treatment or placement, and backfilling or capping the dredged area. This USEPA proposal involves dredging 3.5 million cubic yards of contaminated sediments and subsequent capping, dewatering, and transporting the dredged sediments to a secure disposal site; the project is expected to be completed in 6 to 8 years, making it one of the largest cleanups ever proposed by the USEPA. The USEPA has also proposed using Passaic Valley Sewage Authority’s wastewater treatment facility at Newark as a transfer site for processing dredged sediments. The processed sediments can be transported to the railcars via trucks and then to be disposed at licensed commercial facility. Once capping is completed, there is an opportunity to restore nearly 85 acres of tidal mudflats and wetlands. USEPA anticipates completion of the final design in early 2024 (USEPA, 2023).

The proposed remediation plan is extremely expensive and carries risks of resuspension of contaminants. The Lower Passaic River is a tidal river causing complications with the transportation of dredged sediments. In addition, as one of the most congested regions in the country, the USEPA proposed plan has the potential to cause significant disruptions to economic and social growth of the region, with the closing of several drawbridges to facilitate transport of dredged sediments and finding and operating a large dewatering facility in Newark. This will no doubt restrict the transfer of people, goods and service in, out, and across the region during active dredging and capping periods. The impact on the society due to the current plan includes closing bridges to traffic to move dredged sediments, and risks involve using the river for recreational activities such as rowing, boating, and fishing.

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The Current Status of the
Lower Passaic River

While the design of the dredging the lower 8.3 miles stretch is almost completed, implementation has not begun. Investigations and remedial designs have been occurring on the remainder of the tidal Passaic River, from River Mile 8.3 to the Dundee Dam, which may cost another half billion dollars or so. Different multiple polluters expected to pay for it. Oxychem is supposed to pay for the dredging operations related to the lower Passaic River stretch of 8.3 miles, while the other companies are supposed to pay $150M for the dredging operations of the remaining stretch.

Meanwhile, a partnership of the activist organization celebrates the 10 years of rehabilitation of the river front park along the Passaic, in Newark, specifically Riverfront Park. This restoration allowed children to learn canoeing and artists to find artistic inspiration from the river front. Parks also have been created along the eastern bank of the river from Harrison to Garfield, in part facilitated by the Passaic River Restoration Project in the 1980s as a collaboration between the municipalities, counties and Passaic River Coalition. High school and community rowing clubs use the river (Nicholaides, 2017). However, the river is still contaminated and fishing and swimming in the river are still prohibited. 

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Passaic River Coalition Recommendations
(RM 8.3 to Dundee Dam)

The Passaic River Coalition (PRC) submitted comments to USEPA on June 14, 2021, regarding the interim cleanup plan for the Lower Passaic River from River Mile 8.3 to the Dundee Dam. As proposed by USEPA, the interim action of the Lower Passaic River includes the following:

• Additional capping and dredging in areas with the potential for erosion and high concentrations of contaminants in the subsurface. 
• Areas identified for remediation would be evaluated to determine if sediments at depth in each area can be dredged so that capping would not be needed.
• Dredged materials would be processed at one or more nearby sediment processing facilities for off-site disposal at licensed disposal facilities. 
• Institutional controls such as restrictions on activities in the river would be implemented to protect the cap, and New Jersey’s existing prohibitions on fish and crab consumption would remain in place.
• Monitoring and maintenance of the cap would be required to ensure its stability and integrity in the long term.

“The PRC has carefully studied the technical approaches, concerns and issues related to the interim action of the Lower Passaic River. We understand that the proposed interim action of the Lower Passaic River is tightly coupled with the remedial action OU2, the lower 8.3 miles of the Lower Passaic River, from Newark Bay to river mile 8.3, for which EPA selected a remedy in 2016. The estimated $1.38 billion cleanup plan for that segment is currently in remedial design under EPA oversight.

“The PRC has representation from and is engaged with a broad cross section of stakeholders that care about the future of this river. Throughout this process, we have remained committed to our core values we developed and have stayed focus on a full review of all the possible avenues to achieve a clean and healthy river. We are writing you in response to the proposed interim action of the Lower Passaic River. We would like to bring to your attention the following shortcomings of the proposed interim action of the Lower Passaic River: 

• The PRC believes that success of the proposed interim action of the Lower Passaic River would be significantly constrained by high water velocity during flood periods and intense weather events.
• The high water velocity would also cause higher dispersion of sediments during dredging.
• Also, the proposed interim action of the Lower Passaic River would harm fish migration.
• During high tides, barges carrying contaminated dredged sediments will not be able to pass through low clearance bridges crossing the river.
• The USEPA decided not to cover the proposed cap with a geomembrane, hence low density activated carbon will be lost over time due to buoyancy.
• In addition, USEPA has yet to identify a dewatering facility site that is not in a flood zone and does not have an impact on Environmental Justice (EJ) Communities.
• With high fine content such as silt and clay, we anticipate frequent clogging of the dewatering facility.
• USEPA has not identified a final disposal facility for the dewatered sediments. This site should be fully secure against climate change and should not fail as those did in Tennessee and South Carolina during high intensity storms. Also, this site should not be located in, near or affecting Environmental Justice (EJ) Communities.
• The proposed secure disposal of those contaminated sediments means if compromised those contaminants remain a health risk for current and future generations.”

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Treatment Technology Options

A PRC Board member, Professor Jay N. Meegoda of NJIT, was quite concerned with the shortcomings of the Lower Passaic River Restoration Project and he proposed an innovative solution. To validate his idea, he submitted a proposal to the US National Science Foundation, and he received $460,577 from NSF to investigate his idea (NSF Award Abstract #1634857 Remediation of Contaminated Sediments with Ultrasound and Ozone Nano-bubbles). Over the past five years his research group actively worked on his proposed innovative solution and found that it is fully feasible and can avoid all the above concerns. Also, the implementation cost of this technology will be much lower than the cost estimate given in the USEPA proposal. Hence the USEPA should decouple the technology to be used for Lower Passaic River Restoration Project for the Operating Unit 2 (River Mile 0 to 8.3) and the proposed interim action of the Lower Passaic River and should consider the solution proposed by Professor Jay N. Meegoda for the interim action of the Lower Passaic River.

The technical details of proposed in-situ treatment method are explained in several publications (Hewage et al., 2021; Hewage et al., 2020; Batagoda et al., 2019; Meegoda et al., 2017). This technology will be implemented from a barge, and the sediment treatment chamber will be lowered to the river bottom using a crane, as shown in Figure 1. The treatment chamber is designed so that the generated wastewater does not contaminate the surrounding environment and is directly extracted to the wastewater treatment facility on the barge. The extracted wastewater is treated utilizing nanofiltration and subsequent precipitation before releasing back to the chamber with fresh nano ozone. In addition to the wastewater treatment facility, the barge contains the ozone generator and nano-ozone bubble generator. Once the barge treatment system with all the above is installed, the system will only need chemicals to treat wastewater, power, and oxygen obtained from the air. The power for the system will be generated using solar panels. Hence there is no additional operation cost to treat the river sediments other than chemicals used for wastewater treatment. The proposed in-situ treatment chamber depicted in Figure 1 for field implementation is 10’10’5′ size and details are described in previous publications (Hewage et al., 2020; Batagoda et al., 2019; Meegoda et al., 2017a). This technology can be easily used for the proposed USEPA spot treatment of upstream of the 9-mile marker of the Passaic River. Deploying more than one system as shown in Figure 1 will expedite the Passaic River remediation correspondingly. Meegoda and Perera, 2001 and Meegoda and Veerawat, 2002 showed that ultrasound could desorb both organic and inorganic contaminants attached to sediments. Ozone is applied to prevent re-adsorption of organics by mineralization and to prevent re-adsorption of inorganics by oxidizing and solubilization. Treated and solubilized inorganics are removed by the wastewater treatment unit on the barge. The following are the highlights of above technology:

• A method to remediate contaminated sediments with both organic and inorganic contaminants

• Ultrasound breaks bonds between soils and contaminants and desorbed chemicals. 

• Ozone oxidizes contaminants by direct oxidation and radical reactions. 

• Long-term ozone concentration is enhanced by nanobubbles due to increased solubility and long life of ozone nano-bubbles.

• Insoluble Cr(III) oxidized to soluble Cr(VI) and eventual removal by nanofiltration.

• P-terphenyl degrades by the combined effect of ozone and ultrasound. 

• Results show adequate removal efficiency for both organic and inorganic contaminants.

With the proposed in-situ method with no dredging, transporting, dewatering, transporting and secure disposal would not be impacted by weather, has no dispersion of sediments, no impact on fish migration, no loss of activated carbon, no barges passthrough low clearance bridges, no need of a dewatering facility, no need of a final disposal facility for the dewatered sediments, no health risk for current and future generations and a much lower cost. Hence the USEPA should consider this federally funded in-situ method as the method for the interim action of the Lower Passaic River.

Figure 2. The systematic diagram of the proposed treatment method for field implementation.

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Cited Materials

Batagoda, J.H., Hewage, S.D.A., Meegoda, J.N., (2019), Remediation of heavy-metal-contaminated sediments in USA using ultrasound and ozone nanobubbles. J. Environ. Eng. Sci. 14, 130–138. https://doi.org/10.1680/jenes.18.00012

Center for the Analysis of Public Issues (CAPI), (1972). Pollution Control on the Passaic River. Princeton, NJ.

Hewage, S. A, Batagoda, J. H., and Meegoda, J. N., (2021), “Remediation of Contaminated Sediments containing both Organic and Inorganic Chemicals Using Ultrasound and Ozone Nanobubbles,” Journal of Env. Pollution https://authors.elsevier.com/sd/article/S0269-7491(21)00116-0

Hewage, S., Batagoda, J.H., Meegoda, J.N., (2020), In situ remediation of sediments contaminated with organic pollutants using ultrasound and ozone nanobubbles. Environ. Eng. Sci. 37, 521–534. https://doi.org/10.1089/ees.2019.0497 

Meegoda, J.N., Batagoda, J.H., Aluthgun-Hewage, S., (2017), Briefing: In situ decontamination of sediments using ozone nanobubbles and ultrasound. J. Environ. Eng. Sci. 12, 1–3. https://doi.org/10.1680/jenes.17.00006

Meegoda, J. N., Veerawat, K., (2002), “Ultrasound to Decontaminate Organic Compounds in Dredged Sediments” Soil & Sediment Contamination: An International Journal, Vol. 11 #1, pp. 91-116.

Meegoda, J.N., Perera, R., (2001), Ultrasound to decontaminate heavy metals in dredged sediments. J. Hazard. Mater. 85, 73–89. https://doi.org/10.1016/S0304-3894(01)00222-9

Older rowers flock to Passaic River boat clubs, finding ’emotional connection’

Nicholaides, K., (2017), Older rowers flock to Passaic River boat clubs, finding ’emotional connection’. https://www.northjersey.com/story/news/2017/09/06/more-boomers-taking-up-rowing-passaic/632833001/ 

Passaic River Basin, (n.d.). Passaic River History: From An Informational Placard at the Essex County Environmental Center. https://passaicriverbasin.com/prb2history.html 

US Environmental Protection Agency (n.d.). Diamond Alkali Co., Newark, NJ. https://cumulis.epa.gov/supercpad/cursites/csitinfo.cfm?id=0200613 US Environmental Protection Agency (2023, October). Community Update, Diamond Alkali Superfund Site/Passaic River Cleanup. https://semspub.epa.gov/src/document/02/692920