Below is a list of frequently asked questions about the environmental remediation of the former Harrison MGP site. FAQs are updated periodically based on questions received from the public, including those questions posed during the December 2020 and April 2021 webinars.

 Updated July 2, 2021

What was a Manufactured Gas Plant (MGP)?

Prior to the widespread availability of natural gas, gas was “manufactured” through a process of heating coal in specialized ovens. These facilities, called Manufactured Gas Plants (MGP), were common in many urban areas of the United States during the late nineteenth and early twentieth centuries.  Manufactured gas was used for residential and street lighting and cooking. The manufactured gas process produced byproducts, such as coal tar and other chemicals that were also used in the chemical, dye and pharmaceutical industries. An unintended consequence of the MGP industry was the effects from coal tar and various byproducts to the environment.

Who do I call if I have a concern?

If you have a question, we encourage you to call the Project Information Line at (855) 356-2383 or email the team at comments@HarrisonMGP.com. Kelly Henry is the community liaison working on behalf of PSE&G for the project and will respond to your call or email.

About the Site Remediation

What is the extent of impacts to be remediated? 

The entire 32-acre Site housed the former manufactured gas plant and related operations. As a result, the impacts extend across a substantial portion of the Site. Some of these impacts were remediated between 2004-2018 and the remaining impacts to soil are being addressed through the current remediation.

What is the work schedule and will crew work on the weekends?

The remediation project is a two-year, phased project that is expected to be completed in mid-2022. Typical weekday work hours are 7 a.m. to 5:30 p.m., but may extend to 7 p.m. to complete specific tasks. Saturday work will occur when needed for maintenance and critical activities.

What are the constituents?

The source of the MGP materials is the former MGP operations. Some by-products of the gas manufacturing process, including coal tar residues and oils, are found in the soil and groundwater at the Site. Compounds of concern present in coal tar and oils include benzene, toluene, ethylbenzene and xylene(s) (or BTEX), naphthalene, and polycyclic aromatic hydrocarbons (or PAHs). 

Was any remediation work performed before the current project?

Yes. Since 1999, PSE&G has installed and sampled regularly more than 60 onsite and off-site monitoring wells to determine the MGP impacts to groundwater. At PSE&G’s request, NJDEP first authorized in 2001 and then updated in 2002 a Classification Exception Area (CEA) and Well Restriction Area (WRA) for the entire Site. The CEA identifies where groundwater does not comply with NJDEP standards. A WRA restricts the use of groundwater in a CEA for potable use.

PSE&G performed Interim Remediation Actions (IRMs) to address impacts to soils in 2004-2008, 2006, 2009 and 2011. The remedial actions included a River Front Remediation conducted between the Site and the Passaic River to address migration of Site constituents in the overburden. In 2018, a pilot project, focused on remediating 1.8 acres of the 32-acre site, was successfully completed.

What is the current project?

The current project is addressing impacts to soils that remain on site. The Harrison former MGP Site is being addressed with a combination of different remedies, including the treatment of soils in place, referred to as In Situ Stabilization (ISS). Work is being done in two phases.

What is In Situ Stabilization Solidification (ISS)?

It is a proven environmental remediation process that involves mixing of contaminated soil in place with stabilizing agents, such as Portland cement and blast furnace slag. It solidifies the soil below ground.

What is a Hydraulic Barrier Wall?

Impacted soils in the vicinity of the active M&R Station and its infrastructure will remain in place but contained through installation of a hydraulic barrier wall. Using special machinery, soil and bentonite will be mixed in place down to depths of 60-100 feet to create the wall down to an impermeable clay layer. 

Is NJDEP supervising the work?

In 2012, NJDEP fully implemented the Licensed Site Remediation Professional (LSRP) program. LSRPs provide guidance and oversight to ensure projects like this are performed in accordance with state regulations. The LSRP for this site is John Bolan with PS&S.

The work plan for the Site remediation was reviewed and approved by the LSRP and then submitted to NJDEP, which provided no comments.  After each phase of work is completed, PSE&G develops a report documenting its actions. The report is reviewed and approved by the LSRP and submitted to the NJDEP.

Will work near Frank E. Rodgers Blvd. close a traffic lane?

The work in Phase 2 near Frank E. Rodgers Blvd. will involve ISS and installation of replacement natural gas and water lines for the Site. No short-term or long-term lane closures are anticipated.

However, the sidewalk in front of the PSE&G Site between Cape May Street and Guyon Drive will be closed starting in Summer 2021 for approximately 6 months. Contractor mobilization of equipment and materials to temporarily close the sidewalk may require a limited (1 – 2 day) daytime closure of the southbound lane of Frank E. Rodgers Boulevard closest to the sidewalk.

If any work requires temporarily closing a traffic lane, signs will be posted and the project team will notify the Town of Harrison, the managers of nearby apartment buildings to share with their residents, and post the information on this website. 

Why are you modifying the traffic light at Guyon Drive?

The existing traffic light will be modified to allow traffic from the PSE&G Site to enter and exit the facility. While areas near PSE&G’s Main Gate (across from Riverside Drive) are remediated, PSE&G’s North Gate (across from Guyon Drive) will serve as the only access to the PSE&G Site.

Who is responsible for the remediation of the Site?

PSE&G is the responsible party.

If steel sheeting was installed along the river front, why is this current work necessary?

In 2004-2008, a River Front Remediation was conducted between the Site and the Passaic River to address migration of Site constituents in the overburden. The current project is addressing the remainder of impacted soils on the interior of the Site.

Are any buildings outside the PSE&G property scheduled for removal as part of the project?

No. All buildings scheduled for removal are on the PSE&G property.

Dust Management, Odor Mitigation and Air Monitoring

Does PSE&G control dust during remediation and building demolition?

Yes. Dust control measures such as water misting, and foaming are performed as needed during soil intrusive work.  Water misting also is used as needed during building demolition and materials removal.

How is dust measured?

Dust is measured through the use of photo-ionization detectors (PIDs), both in stations placed around the work site and held by a technician monitoring the site. They provide real-time information about the levels of dust generated near the work areas. When detections are above internally set action levels, additional dust control measures are taken.

Are odors associated with the remediation work?

Soils containing MGP-related materials sometimes have an odor similar to that of mothballs or fresh asphalt. These odors can be detected by people at levels below what can be detected by an air monitoring instrument and well below what would be considered a health concern. Dust and odor control measures (such as water mist, foam spray, plastic sheeting and sand cover) are commonly used to control potential dust and odors during excavation and non-work periods.

Dust and odor assessments are performed at least twice daily, or more frequently as required, to identify and manage observed dust and odors at the source before they travel off site.

If you have a concern about dust or odors, or just a question, we encourage you to call the Project Information Line at (855) 356-2383 or email the team at comments@HarrisonMGP.com. Kelly Henry is the community liaison working on behalf of PSE&G for the project and will be the first person to respond to your call or email.

Are odors a health concern?

Odors associated with some MGP constituents can often be detected at levels that are below a health concern and often below what can be detected by an air monitoring instrument. While the project team is committed to minimizing them, odors similar to fresh asphalt or mothballs will at times persist.

The project’s perimeter air monitoring is focused on protecting public health. Perimeter air monitors are set to an internal threshold well below any health concern. If the internal threshold is triggered, additional actions are taken, such as water misting or odor suppressing foaming.

Will there be a smell of natural gas during the remediation?

MGP constituents commonly smell like fresh asphalt or moth balls. Natural gas, which has no odor, adds an odorant called mercaptan that smells like rotten eggs.

If you smell rotten egg odors associated with natural gas for more than 10 seconds, call 911.

What is used to control vapors and odors and what is in it?

The foam at the project site is made from a Rusmar brand foam concentrate, specifically Rusmar formulas AC645 and AC900. Both serve to form a barrier between constituents and the atmosphere and are applied either during or after active excavation to provide an immediate and effective barrier to vapors and help to minimize odors. Short-term odor suppressing foam is white in color when applied. Long-term odor suppressing foam is black in color when applied and dries to a dark gray or black color with a shiny appearance. Both are completely biodegradable. Neither formula has an inherent odor; however, a scent (such as wintergreen, cherry or vanilla) may be added.

Rusmar AC-645: http://www.rusmarinc.com/_assets/img/PDFs/new/AC-645-RusFoamOC-MSDS.pdf

Rusmar AC-900: http://www.rusmarinc.com/_assets/img/PDFs/new/AC-900-RusFoam-LM-MSDS.pdf

In addition, SL Super 9, a surfactant, is being used as an additional vapor suppression product: https://harrisonmgp.com/wp-content/uploads/2020/10/SDS-SLSUPER9_Cherry.pdf 

Will air monitoring be performed?

Yes. An air monitoring plan specific to the site’s activity and constituents of concern has been developed and is being implemented. Air monitoring is performed when building demolition, digging, or any soil disturbance activity, is performed.

What do the air monitors do?

Air monitoring stations are installed along all sides of the work area perimeter and between the project area and the closest building when remediation work is being performed.

The stations house two monitoring devices that will operate continuously during active work hours. One device is a photoionization detector (PID), which is a type of vapor detector. It monitors and records total volatile organic compounds (TVOCs). The other device is a real-time particulate matter meter that monitors for dust.

The stations are closely monitored to ensure that the project stays below health-based action levels. A summary of air monitoring results is posted to this website after results are confirmed by an independent laboratory.

Where are the air monitors stationed?

There are currently eight air monitoring stations located along each of the north, east, south and west sides of the work area perimeters. Monitors may be moved as work areas change.

How quickly do you get air monitoring results?

While remediation is being performed, perimeter air monitoring equipment provides real-time readings, continually measuring and recording TVOCs and PM-10 (a measurement for particulates or dust) to the project team during work hours.

Additionally, an air sample is collected weekly during remediation activities and sent for analysis at a New Jersey certified laboratory. These results are expected within three to four weeks of the collection date, and the current running average is posted on the Air Monitoring page.

The Air Monitoring page on the website provides only data for Benzene and Naphthalene. Are they the only constituents you monitor?

No. In accordance with the Perimeter Air Monitoring Plan, air samples are analyzed for the full suite of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and metals (the MGP constituents of concern).

If levels for Benzene and Naphthalene are below the PAMP action level, then there is no indication that any of the remaining MGP constituents of concern are at risk of exceeding the residential health-based standards. These MGP constituents of concern are monitored in accordance with the PAMP and can be shared by request.

Project Noise

Are you required to seek permits from the state or the town for construction noise?

The Harrison MGP remediation project is considered a construction project by the State of New Jersey and the Town of Harrison, and the work produces typical construction sounds. The State of New Jersey and the Town of Harrison view construction projects as temporary projects that do not require a noise permit.

The project will notify residents, both through weekly email updates and on HarrisonMGP.com, when work is expected to create noise, such as from breaking up concrete or building demolition.

Will residents hear noise from equipment?

Residents will hear noise from equipment similar to any construction project. The project will notify residents, both through weekly email updates and on HarrisonMGP.com, when it anticipates work will create noise, such as from breaking up concrete or building demolition.

Are the noises from the site safe for human levels?

Yes. Workers are provided personal protection equipment, including ear plugs, to use at their discretion but levels do not require they be worn.

Drinking Water

Will this work impact local drinking water?

Groundwater in the area is not used as a potable water source and the Town of Harrison water supply is not affected.


Will you place vibration monitors on buildings across from the project?

Our vibration monitoring plan, created by an outside expert, places vibration monitors at buildings closest to the work to ensure they are protected from damage. The monitors measure ground vibration, which dissipate with distance. So, if the closest buildings are protected, buildings further away are also protected. 

I felt my entire apartment shaking during the day. Will this happen often?

Remnants of the former MGP facility are below ground and must be removed. You may feel vibrations as concrete is broken and removed. These activities will not be every day and the locations will change as the projects clears new areas.

About the Pilot Project Remedy

How do you know the pilot study was successful?

The mixture of stabilizing agents used in the ISS process varies from site to site and is determined based on the conditions of the soil and groundwater. The success of the ISS remedy was determined by taking cylinder samples as the mixture cured and assessing whether the stabilized soils met a minimum strength, maximum hydraulic conductivity, and leachability. Testing determined the process worked as designed.

Future Use of Site

What is the future use of the PSE&G property?

The PSE&G Site Remediation Group is not aware of any immediate plans to alter the property’s current use.

Will the remedy impact any future development on the property?

No. The remedy will not prevent future development of the Site.

How will the site be graded and finished after the remediation is completed?

The site will be restored to the current site grade with clean fill and gravel. Some areas where asphalt was removed will be repaved.

Will the fence line remain the same at the end of the project and who will be responsible for site maintenance?

Yes. The perimeter fence line will remain and be maintained by PSE&G. Temporary fencing around work areas will be removed once work in those areas is complete.

However, the remediation project is one of many onsite activities. Other PSE&G operations onsite can be called in at any time, as necessary.