O&R has begun work on a clean-up project, including the removal of approximately 20,000 cubic yards of coal-tar impacted soil, at the site of a manufactured gas plant (MGP) that closed its doors nearly 80 years ago on Pat Malone Drive in the village of Suffern.
The project is expected to last seven to nine months and cost between $11 million and $13 million.
Manufactured gas plants (MGPs) were operated from the early 1800s until the mid-1900s to produce gas from coal for lighting, cooking and heating. MGPs were phased out after World War II because natural gas had become available across the nation. There are more than 1,500 sites throughout the country and more than 250 sites in New York State.
The various processes used at manufactured gas plants involved heating coal to high temperatures to produce gas, often generating byproducts and residue. The most common MGP by-product is coal tar. In the absence in bygone days of modern environmental science and regulations, coal tar and other MGP residues that can impact human health and the environment were typically abandoned on the MGP sites after their closings.
The coal tar at the Suffern site will be mitigated in three ways:
- Removal of the subsurface MGP holder and the gas oil house structures,
- Excavation of approximately 20,000 cubic yards of coal-tar contaminated soil to approximate depths of 10-15 feet and off-site disposal, and,
- In areas of deeper contamination of up to 35 feet, solidification and entombment of approximately 17,000 cubic yards of impacted soil by mixing it with cement using an excavator or augers.
Most of the site excavation activities will take place under two large tent-like fabric structures (approximately 96 feet by 115 feet and 131 feet by 131 feet) with a carbon-filter, air-handling system. These temporary structures will be moved around the property as work is completed and new work is begun.
The fabric structures will control vapors — similar to those from roofing adhesive or driveway sealer — and dust generated during the excavation of soil that is impacted with coal tar. The effectiveness of the structures will be verified by real-time air monitoring conducted 24-hours a day, seven-days per week during the project. The structures and air monitoring together will help ensure that neighboring residents are not exposed to dust and vapors from the excavation above the New York State Department of Health (NYSDOH) established guidelines.
Some excavation will be performed at smaller areas on the site outside of the structures. If coal tar odors emanate from that digging, retardant foam treatment will be topically applied to the soil to neutralize the odor.
As part of this project, a Groundwater Monitoring Plan has been established to ensure adequate notification to the Suffern Water District, the New York State Department of Environmental Conservation (NYSDEC) and the Rockland County Department of Health in the event that a migration of site-related MGP impacts is detected in the groundwater. If that occurs, an active response plan is in place and would be initiated to ensure the health and safety of the public water supply.
Sentinel wells have been in place monitoring the ground water between the site and the village water supply well since 1999. During that time, no impacts to the water supply wells have been found.
The excavated soil will be trucked off site for thermal treatment and disposal to an approved, licensed facility in Keasbey, N.J. Clean fill will be trucked in to replace the excavated soil. All trucks and equipment leaving the site will be cleaned before driving on neighborhood roads. All trucks hauling impacted material will be sealed and covered.
Trucks departing the site will take a left turn onto Pat Malone Drive, a right turn onto Ramapo Ave. and a right turn onto Route 202 and follow that road to Route 17 toward the disposal facility.
After the mitigation work is complete, an environmental easement will be placed on the site that will allow the use and development of the property for commercial or industrial uses subject to local zoning laws. The easement also will restrict use of the on-site groundwater there as a source of potable or process water.
The project’s work will be performed Monday through Friday between the hours of 7 a.m. to 5 p.m. Noise levels will be consistent with a typical construction project. Security will be provided on the site during evening hours and weekends and holidays.
The project construction offices will be housed in trailers on site and staffed during business hours by supervisors from the principal contractor, Creamer Environmental Inc. and O&R’s Construction Manager and Engineer. The project site is a construction area and is not open to the general public. Questions from the public about the work and/or the site should be directed to O&R at (845) 858-0018.
O&R currently operates a natural gas regulating and metering station on a small section of this property. Station operation will remain unaffected by this project. The parcel is zoned for manufacturing land use. O&R currently has no plans for the future of the property except for its current use.
The NYSDEC and the NYSDOH have been working with utilities across the state to identify, investigate and clean up these sites if necessary. O&R has been working cooperatively with NYSDEC and NYSDOH since 1996 to investigate seven MGP sites, formerly owned by O&R predecessor companies, and has successfully completed clean-up projects in Haverstraw, Nyack and Port Jervis.
The Suffern manufactured gas plant, owned by a predecessor company of O&R’s, operated at this site from 1902 to 1935. During the 1940s and early 1950s an electroplating facility was in operation at this location. More recently, a bus manufacturer operated there until 2008 when O&R purchased the site and demolished the bus building in order to perform the cleanup.