Minimizing the impact on air quality, water quality and noise effects from our manufacturing process.

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ROCKWOOL stone wool insulation is manufactured according to strict environmental standards

Protecting the environment in the communities we operate is our number one priority.

A history of environmental leadership

80 years of manufacturing stone wool has taught us how to excel in the manufacturing process.

Today, we only build factories that leverage state-of-the-art technology and equipment.

As a result, the products we manufacture have an enormous positive impact on society and address many of today’s global sustainability challenges.

Our new facility in Ranson will not only be fully compliant with both local and national regulations but will use the latest in environmental technology and advanced production equipment.

We’re continually focusing on reducing environmental impact by investing in the development of more environmentally friendly solutions in all our manufacturing facilities.

The new production plant in Ranson will implement the most advanced emission control technologies developed to date.

Air Quality

ROCKWOOL takes air quality and any threat of air pollution seriously.

Our manufacturing process meets or exceeds the most stringent environmental regulations, and the facility in Ranson will incorporate the best available control technologies.

The regulations we follow are set by the Federal Clean Air Act (shown below) and MACT (Maximum Achievable Control Technology) standards.  Both of these standards were developed and issued by the U.S. Environmental Protection Agency (EPA) and set maximum permissible emissions for key substances.

The MACT standards were most recently expanded in 2015 and accepted by the Sierra Club – a national organization that been involved in raising the standards for numerous industries, including mineral wool production.

These standards were designed to provide “an ample margin of safety for human health and the environment,” including impacts from VOCs such as formaldehyde, phenol, and methanol

The Sierra Club, in fact, was a very active participant in the entire rule-making process and ultimately accepted the new industry standards.

The equipment, technology, and production processes leveraged at the Ranson, Jefferson County site will ensure that we are protective of both human health and the environment in Ranson.


Structure of the U.S. Federal Clean Air Act with supporting abbreviations.

Based on all available information that we have gathered and that we have reviewed, we see no threat to the health of our citizens and no threat to our environment.

Austin Caperton

WVDEP Cabinet Secretary
Download the DEP letter

We use abatement technology to control and minimize emissions

We use what is called “Wet Electrostatic Precipitator” (WESP) technology for emissions control. The WESP uses electricity in a wet environment to electrically charge and collect particles.

On average, this process reduces air substances between 95-99 percent. This is highly efficient and considered a Best Available Control Technology (BACT) for PM 2.5 (particulate matter 2.5 microns).

Additional abatement (emissions minimizing or reducing) technologies will reduce the concentration of volatile organic compounds (VOCs) and oxides of nitrogen (NOx) to a level defined as “insignificant” by the National Ambient Air Quality Standard (NAAQS).

Some community members have asked about “wet scrubbers.” Some such approaches can also be effective for emissions control, but using this type of technology creates a stream of wastewater, which we want to avoid.

Looking for proof? We worked in collaboration with a German town helping them achieve clean air resort status. See the full case study.

See below for a diagram of the abatement system that will be implemented at the Ranson facility (image one of the carousel), as well as a visual of the WESP process and how it works (image two).


The ROCKWOOL abatement process reduces the concentration of substances in air emissions.

rockwool-wesp-abatement-technology-what it is-how it works-ranson-wv

Wet Electrostatic Precipitator (WESP) technology for emissions control - process and how it works.

ROCKWOOL is using the best practices available to minimize any negative effect on the environment and the company continues to work toward improving its processes.

Patsy Noland

Commissioner, JCC

Air monitoring in Jefferson County

Together with a third-party, we are currently undertaking a science-based study looking at climatological data and air modeling to recommend the most appropriate air quality monitoring set-up.

Once the study is complete, ROCKWOOL is committed to both monitoring and making publicly available air quality data in the area around our Ranson, WV plant.

ROCKWOOL will cover the costs of installing and having a third-party operate the air quality monitors.

Our intention is to have the stations ready in mid-2019 to ensure a full year of baseline data collection prior to opening the facility.

The parameters for what should be monitored and where the monitoring should occur is being governed by the scientific relevance of various substances in relation to the ROCKWOOL facility.

We are also taking into account community feedback and concerns about sensitive areas including North Jefferson Elementary School.

Once suitable locations have been identified, it will be necessary to secure permission from relevant landowners to place monitors on their property, ensure access to a power supply, and to secure any permits that may be required.

ROCKWOOL Ranson air quality modelling of formaldehyde at schools in the community shows levels are below VA limits.

ROCKWOOL Ranson air quality modelling of formaldehyde at schools in the community shows levels are below VA limits (no limits in WV).

Air permit and governing standards

Recently, research was completed by important governing standards and legal limits applicable to our industry from the National Ambient Air Quality Standards (NAAQS) and the Maximum Achievable Control Technology (MACT) standards – both of which were developed and issued by the U.S. Environmental Protection Agency (EPA).

This research and analysis support the determination that the ROCKWOOL facility in Ranson will have no negative consequences in Jefferson County or in neighboring counties such as Loudoun. Additionally, these stringent standards are designed to be protective of sensitive populations like children, asthmatics, and the elderly under worst-case scenarios.

When the MACT standards are next reviewed, we fully expect ROCKWOOL’s exemplary environmental performance will positively influence the setting of future limits. We’re proud to be helping shape such important industry standards.

The equipment, technology, and production processes leveraged at the site will ensure that we are protective of both human health and the environment in Ranson.

The Air Permit issued to ROCKWOOL will ensure that the facility will meet strict air quality limits stipulated in the Federal Clean Air Act and in West Virginia. The WVDEP re-affirmed their assessment with a statement, “Air permit approved by WVDEP met strict state and federal standards that are protective of human health and the environment,” provided via a letter dated September 18, 2018.

ROCKWOOL applied for an Air Permit with support from our consultant “Environmental Resources Management” (ERM) to the West Virginia Department of Environmental Protection (WV DEP) in November 2017 before its approval by the WV DEP and review and acceptance from the U.S. Environmental Protection (EPA). ROCKWOOL will continue to work closely with both organizations in the regulation of air quality.

As part of the permitting process, the WVDEP has created a Rockwool Facility project webpage dedicated to informing concerned residents about the current status of this project. The resources available include information about the air permit, construction stormwater permit, and correspondence regarding the facility.

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What is the significant impact area?

The maximum significant impact area is defined by the Environmental Protection Agency (EPA) and it is the maximum distance from the facility where it is required to perform the modeling and calculate the contribution of the facility on air quality to provide compliance with standards.

That distance varies for different components. In the case of the ROCKWOOL Ranson facility, it has been modeled up to 35 miles from the facility.

EPA Inventory of Jefferson County air pollution

Did you know that more than 94 percent of air pollutants in Jefferson County are emissions that will be generated by sources other than our new facility in Ranson?

Based on the recently published National Emissions Inventory (NEI) data from the EPA, we analyzed the emissions inventory of Jefferson County for all air pollutants and compared it to our Ranson facility permit.1

The breakdown of the data reveals that when operational, the emissions from our facility will be vastly outweighed by other, non-regulated sources.2

These sources include emissions from local, everyday activities. The EPA data shows that non-regulated sources are the primary contributor of emissions in Jefferson County.

EPA air emissions breakdown

In all but two categories, our emissions will be in the teens or single digit percentages for Jefferson County. 

The majority of emissions can be attributed to transportation, dust, agriculture, and combustion. More specifically, the most significant sources of air pollutants come from traffic, road dust, vegetation, and soil.

See the images below for more details.

ROCKWOOL EPA Air Emissions Jefferson County, West Virginia

ROCKWOOL maximum and expected air emissions data for Jefferson County, West Virginia.

ROCKWOOL EPA Air Emissions Jefferson County, West Virginia

ROCKWOOL EPA Air Emissions Data for Jefferson County, West Virginia.

Sources of direct air emissions in Jefferson County, West Virginia

For starters, what are air emissions?

According to the United States Environmental Protection Agency (EPA) emissions is the term used to describe the gases and particles which are put into the air or emitted by various sources.

What do we mean by direct air emissions?

The EPA National Emissions Inventory (NEI) data is a comprehensive and detailed estimate of air emissions calculated based on substance levels originating from sources within the county’s geographic boundaries. Not included in these figures are the air emissions transported from upstream sources. The reason for the EPA not including upstream data is the requirement to complete separate modeling that accounts for meteorological patterns among other factors. This modeling is done on a less frequent basis than the NEI study which is published every three years.

How are air emissions measured?

Every three years, the EPA works with air pollution organizations, industry, and researchers at the state, county and local levels to compile a comprehensive summary of air emissions data known as the national emissions inventory (NEI). The NEI is based on a set of data that serves as the most comprehensive national and local view of emission estimates for criteria and hazardous air pollutants.

What are the primary source types?

Emissions in Jefferson County, WV as with all counties, states and at the national level are broken into two source types – point and nonpoint. A point, or single emitter source, refer to emissions sources from a fixed location such as a farm, industrial facility or commercial institution. Non-point sources are often termed ‘diffuse’ and are defined by sources that may be abundant and smaller in magnitude and generally occur over a wide area not easily attributes to a single source.

Air emissions in the Jefferson County community

In reviewing all sources of air emissions outlined in the 2014 EPA NEI dataset we have developed an educational analysis of individual substances in Jefferson County, WV. The figures and information used below include the contribution from various existing industry sectors as well as any impact from the expected emissions from the new ROCKWOOL Ranson facility. Expected emissions are based on measured data from ROCKWOOL installations of comparable size and technology. 

What other resources are available to the public to learn more?

The EPA provides access to air quality data collected at outdoor monitors across the state with the closest location being in Martinsburg, WV. There is also an annual report on air quality published by the West Virginia Department of Environmental Protection.

For more information download the NEI source type fact sheet.

EPA National Emissions Inventory

Industry sectors

The NEI data is separated by industry sectors and within each sector, there are several sources of emissions. Below are those relevant to our analysis of Jefferson County data and examples of specific sources for each sector:

Agriculture: crops and livestock dust, fertilizer applications, and livestock waste.

Biogenic: natural sources such as vegetation and soil.

Dust: construction dust, paved road dust, and unpaved road dust.

Fires: agricultural field burning, prescribed fires, and wildfires (excludes home fires).

Fuel combustion: composed of residential, commercial and industrial sources of energy creation including biomass, coal, natural gas, oil and other. 

Industrial processes: storage and transfers as well as pulp and paper production.

Miscellaneous: bulk gasoline terminals, commercial cooking, gas stations, and waste disposal.

Mobile: aircraft, commercial marine vessels, locomotives, non-road diesel, non-road gasoline, on-road diesel vehicles, on-road non-diesel vehicles.

Leading annual sources of air emissions by substance in Jefferson County, West Virginia. CO, Lead, PM, Benzene, Sulfur Dioxide, Nitrogen Oxide, Formaldehde, and VOCs.

Case study: ROCKWOOL and Flechtingen: a partnership in clean air

While the most significant positive impact on sustainable development we have is through the use of our products, it is important that we achieve this by operating in a responsible and sustainable way - continuously reducing the footprint of our operations.

Becoming a healthy community takes the efforts of industry, government, and local residents, working together.

In 1990, when we took over a facility in the town of Flechtingen, Germany, our priority was investing in new and innovative technologies to improve environmental conditions.

Similar to Jefferson County where tourism is a year-round industry and one of the top drivers of economic development, Flechtingen welcomes thousands of patients and tourists annually.3

The partnership between the town and industry including ROCKWOOL helped the town, located just a half mile from our factory, achieve ‘clean air resort’ status.

The requirements for clean air resort status according to Kora Duberow, Manager of the Flechtingen Community Tourist Department of Wellness and Therapy "are many and include first and foremost maintaining air quality levels at the most stringent of levels."

Flechtingen achieved clean air resort status in 1999 with ROCKWOOL factory just a half mile from the town.
We’re about 300 meters from the factory… There’s no noise or smell or anything else from the factory because the environmental conditions and equipment is so state-of-the-art.

Berndt Gabriel

Resident of Flechtingen

Assessing the environmental impact of three substances

We brought in ERM as a third-party environmental consultancy. Even if not required by the permitting procedure we tasked them with conducting a thorough assessment of the expected levels of three specific substances: formaldehyde, phenol, and methanol. These substances are not currently regulated in West Virginia.

The model method used to assess our contribution toward air emissions confirmed that the facility in Ranson will meet strict chemical substance limits. For these three pollutants, we assessed the yearly average impact in the proximity of the factory to be as follows:


The allowable limit under Virginia regulations


The allowable limit under Virginia regulations


The allowable limit under Virginia regulations

Air Quality in Loudoun County

Given Loudon County’s distance from Ranson and that pollutants dissipate over such distance, the impact on Loudon County will essentially be non-existent.

Based on the extensive modeling done related to securing the air permit, we calculated the maximum impact Loudon County can expect from NO2 (nitrogen dioxide), SO2 (sulfur dioxide), and PM2.5 (particulate matter 2.5 microns – the smallest particulates measured) from the ROCKWOOL manufacturing facility in Ranson, WV.

The yearly averages for NO2, SO2, and PM2.5 will be less than one percent of the federal limits (National Ambient Air Quality Standard - NAAQS) for ambient air concentration. 

There are several DEP programs involved in the regulation and pollution control at the Ranson site. This includes programs involved in the construction phase, and once the plant is operational.

The site is currently under the DEP’s Division of Land Restoration’s Voluntary Remediation Program, which oversees cleanup and redevelopment of industrial sites as well as a Construction Stormwater Permit through the DEP’s Division of Water and Waste Management.


Impact on air quality in Loudoun County from the ROCKWOOL Ranson facility.

Water in the Production Process: inflow, usage, and outflow

Water is a critical component of the ROCKWOOL insulation production process and a resource that needs to be protected. In fact, as an organization, we have ambitious goals to reduce water usage across our global operations. It is one of 10 United Nations Sustainable Development Goals we have committed to contributing toward achieving. 

We believe in continuous improvement to uncover more efficient technologies for our production processes. This includes the development of an internal closed-loop system that will be implemented at the Ranson, WV facility. With the closed-loop system, rainwater will be collected in secure on-site ponds and used as the primary source of water in the production process. Once the water is brought into our production buildings, it does not leave those production buildings. The specific design elements that contribute to ensuring the protection of the karst geology of the area include:

  • The production process water is in a closed loop (understanding that some will naturally evaporate).
  • Storage tanks will be in secondary containment and both the tanks, as well as the pipes connecting them, will be above ground to enable close monitoring of the system.
  • No water is discharged from our production process into the rainwater ponds as their sole purpose is to allow for the collection, storage, and usage of rainwater. 

These collection ponds have both been designed with enough capacity to withstand a 100-year storm event.  There are two rainwater collection ponds, one is within the closed-loop system serving as the primary source of rainwater, the second will provide additional rainwater for production and will be permitted to discharge excess rainwater to a discharge area in compliance with the relevant permit.

There is no production water discharged into the municipal sewer system or released into the environment. In fact, no production process wastewater is discharged into waterways or the ground at any of our manufacturing facilities. ROCKWOOL has designed the factory in Ranson, WV to prevent contamination of the soil and groundwater by taking several measures – most notably that tank loading and unloading areas will capture and manage any incidental spills, and the binder used in the production of our stone wool insulation products will be stored in a containment area, under a covered roof, in above-ground storage tanks.

In cases when rainwater is not sufficient for the production process, water supply will be supplemented by Jefferson Utilities, Inc. (JUI), which will provide the waterline to the factory for water service. Our water demand from JUI will not exceed 125,000 gallons per day. Based on a county-wide estimate of the annual available groundwater, our consumption will be less than one percent of the total available water supply.

Taking this approach is consistent with our global sustainability strategy to minimize the use of drinking water in our production processes. ROCKWOOL has been recognized internationally for our commitment and approach to sustainability, which you can read more about in our 2018 sustainability report.

The only water that will be discharged from the Ranson site into the sewer system is from sinks and toilets as well as water from the purification process. Any drinking water we take in from the water utility is purified for use in the industrial process by removing lime and other minerals, and then the residual is discharged into the sewer system. The discharged wastewater contains a similar mineral makeup to what’s in the utility-provided supply albeit in greater concentrations (ca. 4x).

The maximum volume of residual water from the purification process that will go to the Charles Town Waste Water Treatment Plant (CTWWTP) per our NPDES permit is 14,900 gallons per day (GPD).

The visual below shows the closed loop system and how we utilize rainwater capture as part of a process that eliminates production process wastewater discharges into any waterways, sewer systems or the ground.

Monthly Newsletter

Join our mailing list

Keep updated with the latest news and information on the ROCKWOOL development in Ranson, Jefferson County by subscribing to our eNewsletter.

Microsite Sizing: Ranson, West Virginia factory waterline and sewer line system diagram including all inflow and outflow of water from the facility. Includes details about the water in the closed-loop production process - water supply, stormwater collection pond. production water reuse pond.

ROCKWOOL Ranson, WV factory water system diagram shows an overview of the water and sewer line infrastructure supporting the closed-loop production process.

Noise levels from the factory

During operation, the Ranson facility will not cause unwanted noise pollution as the noise levels emitted will not exceed what is permitted in the community.

Based on our experiences from other factories that we operate near neighborhoods and schools, we do not anticipate levels above 50 dB at a distance of approximately 1,550 feet. Noise-abating technologies will be applied to further reduce any potential impact.

At ROCKWOOL, we strive to maintain strong relationships with our neighbors through open communication and have managed to accomplish that with our factories in North America and around the world.

We take complaints seriously, investigate and take immediate corrective actions.

See below for a map of the minimal noise impact from the factory and a second visual showing the drastic decrease in the volume of complaints in North America since 2014 (includes noise among other sources of complaints).

ROCKWOOL ensuring minimal noise around RAN5 factory for ranson, jefferson county, wv community

ROCKWOOL is taking precautions to ensure minimal noise around the factory in the Ranson community.

rockwool-historical-volume-of-complaints-by-factory-milton-byhalia-grand forks

Historical development in number of complaints by North American factory - updated October of 2018.

We can co-exist with an environmentally-conscious local community and ensure industry, agriculture, tourism, and trade.

Marco Boi

Production Operations Director, ROCKWOOL
See the full Spirit article


1EPA Jefferson County Inventory, 2014 (data published in July of 2018)

2Phenol is not included in the EPA database but does appear in our permit.

3Jefferson County Development Authority - Tourism

Find additional information about the ROCKWOOL project



Who is ROCKWOOL and what is stone wool insulation?

Find out answers to these questions and more with information about our organization, its history and values, and an overview on the materials we use in manufacturing.

Learn more


Community and Economic Impact

We seek to make a positive impact in the City of Ranson and more broadly Jefferson County.

Through economic development that brings jobs for residents, opportunities for local businesses and support for local community organizations, we are focused on furthering the well-being of the community where we live and work.

Learn more


Jobs and Vendor Opportunities

150 jobs coming to Ranson, WV. Hiring starts in 2019.

ROCKWOOL is providing new manufacturing jobs in Jefferson County with an exceptional culture, wellness programs, investments in learning and development, and dedicated corporate social responsibility. We will also provide new vendor partner contract opportunities once the factory is in operation.

Learn more



At ROCKWOOL, sustainability is always top of mind.

Responsible business practices underpin everything we do. Sustainability is not only important for our products and brand, but also for our production process. We have ambitious targets for 2022 and 2030 to further reduce our environmental footprint in compliance with United Nations sustainability goals.

Learn more


Factory Operations and Production

Interested in how our stone wool insulation is made?

The ROCKWOOL manufacturing process includes an overview of insulation being made and what it’s made of, day-to-day operations of the plant and insight into the visibility, water usage and trucking and transportation impacts for Jefferson County.

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Construction and Permitting

An overview of the air, construction and environmental permits required.

Access detailed information regarding site selection for the factory, development and environmental management of the project.

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Documents and resources



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