Environmental Journeys: 14. Town Gas

I remember my mother taking me and my brother to see the Disney movie Lady and the Tramp. Decades later this movie would enter professional environmental circles as fun conversation in connection with Town Gas. Little did I know when I first saw the movie that I was looking at scenes that would later influence my work life. The scenes include little things like turning on the wall light with a basket of matches on the wall in the background and taking a buggy ride down a road in the direction of a large structure on the horizon passing gas-lit streetlamps along the way. Those frames of the movie are connected by energy.

A few scenes from Lady and the Tramp illustrating the Gaslight Era. In the upper left, a gas lamp is being turned up; in the lower left a horse-drawn buggy makes its way down a street with gas lamps with a gas holder on the horizon; Lady and The Tramp are enjoying their dinner. Photos are taken from the Disney movie.

The energy was in the form of manufactured gas often referred to as Town Gas or Coal Gas because it was primarily manufactured from coal. The gas was made at a local manufactured gas plant (MGP), stored in large gas holders such as the one seen on the horizon in Lady and the Tramp, and piped through the streets of towns. The commercial source of this energy first emerged in England around 1800 and quickly spread into Europe and North America. The manufactured coal gas would light the homes of our ancestors a few generations back, a time referred to as the Gaslight Era.

The use of manufactured Town Gas diminished during the 20th century, giving way to electricity and natural gas as sources of light and heat. But the waste byproducts of the gas manufacturing operation would typically remain near the source of the production, sometimes on the site and sometimes at a nearby disposal area. The two predominant forms of waste that emerged decades later as environmental issues are coal tar and purifier waste. I am writing this at my kitchen table in Troy, New York. The state had many MGP sites, including one down the street from me. The New York State Department of Environmental Conservation oversees the remediation of MGP sites within the state and provides succinct and informative descriptions of the history, nature of operations, and remediation of MGPs in a website that includes General Information about MGPs.

Regarding the two major waste types that drove most of the environmental studies and remediation at MGP sites, New York DEC describes them as:

• Coal Tar: A dense, oily liquid known as coal tar would condense out of the gas at various stages during its production, purification and distribution. Although most of the tar was collected for sale or reuse, recovery was incomplete. Most plants had tar/water separators, which sometimes could not fully separate the two liquids. The resulting tar/water emulsion was often discharged to a nearby surface water body. Over the decades during which many of these MGPs operated, substantial amounts of tar also leaked from storage and processing facilities and contaminated surface soils, subsurface soils, and groundwater. Today, at a number of former MGP sites, tar or tar/water emulsions continue to migrate slowly in the subsurface and may enter into sewers, basements, or nearby surface water bodies. Under some conditions, tar will temporarily float on the top of surface water bodies, creating oily sheens on the water surface. However, in most cases, the tar will sink to the bottom, leading to contamination of sediments. Whether present due to historic disposal or continuing migration, coal tar may impact water quality and the organisms which live or feed in the sediment.
• Purifier Waste: Another byproduct -purifier waste- was made up of either lime or wood chips treated with iron oxides to remove cyanide and sulfur from the manufactured gas. Once it had become saturated with impurities, purifier waste was often discarded or used as a fill material. This waste often contains complexed cyanide compounds which can contaminate groundwater. Purifier waste also generates a strong, objectionable odor when it is exposed on the ground surface. For more information on these MGP wastes, see the section on MGP Wastes.

A picture of a MGP Site is shown below from the report cover of the state’s approach to the remediation of MGP sites..

Serendipity

It seems that serendipity threads through my stories, so I looked up the definitions.

• Serendipity is luck that takes the form of finding valuable or pleasant things that are not looked for. (From Webster Dictionary)
• Serendipity is the occurrence and development of events by chance in a happy or beneficial way. (From Oxford Dictionary)

Serendipity played a large role in how I became involved with environmental studies of MGP sites. We can all look back and see how serendipity shaped our lives. But before I share my story of serendipity and the MGP world, I’d like to pick up on the end of Webster’s definition …things that are not looked for. To be successful, amalgamated to that phrase are the notions that:

• You make your own luck, referred to as Synchronicity: creating your own luck through your own efforts.
• In the fields of observation chance favors only the prepared mind (Louis Pasteur at a lecture at the University of Lille in 1854).

I found all of these ingredients — serendipity, effort, and preparation — essential to my career as an environmental consultant. In many ways serendipity is the payoff for the other two. Regarding environmental and engineering consulting on MGP sites, the events that led to lifelong careers for me and my colleagues unfolded as follows. It begins with a 1984/1985 report by Robert Eng of the Radian Corporation entitled Survey of Town Gas and By-product Production and Locations in the U.S. (1880–1950).

• EPA has been aware of potential environmental issues at MGP sites at least since the early 1970s and wanted to understand and document the magnitude of the problem. The 1984/1985 Radian Report for EPA reported a widespread distribution of 1,500 MGP sites across the United States and the number was suspected by subsequent research to to be much greater, perhaps as many as 5,000. This finding created concern and perhaps alarm among the gas and electric utilities, environmental agencies, and organizations such as the Gas Research Institute (GRI) a not for profit organization that provides research support to member companies in the gas industry.
• Dave Linz, a 32-year old chemical engineer working at GE’s nuclear facility near Wilmington North Carolina, was looking for a change in career and geography for him and his young family. His resume arrived at the Gas Research Institute (GRI) in Chicago Illinois. The head of GRI’s research program was also a chemical engineer and Dave’s resume and the fact that he too was a chemical engineer was appealing. Dave was hired to take on the emerging MGP issue and the young family moved to the suburbs of Chicago. Early in his tenure at GRI, Dave receives a visit from Dave Nakles, a Principal at the consulting firm ENSR. Dave Nakles had been working on underground coal gasification with its associated environmental issues and he thought that experience would be useful for approaching the MGP matter.
• Contemporaneous with the emergence of the wide-scale MGP matter, Dennis Unites and John Ripp of TRC were working on the Brodhead Creek Superfund Site in Stroudsburg Pennsylvania. An MGP site operating from 1888 to 1944 had contaminated creek sediments, water, and soils of the 12-acre site with coal tar. Jim Villaume of Pennsylvania Power & Light (PP&L) had contracted TRC for the work and gotten to know Dennis and John who had taken up temporary residence at a nearby cabin to oversee the work. One night while leafing through the Radian Report, Dennis was struck by the large number of MGP sites. He looked up at John and the two discussed the possibility of forming a company with a focus on evaluating and remediating MGP sites. They together with Paul Burgess then formed Atlantic Environmental. (Years later Atlantic Environmental was acquired by GEI which continued the MGP work and organized biannual MGP conferences.)
• I started my company with a focus on being the risk assessment arm of environmental engineering firms. One of those firms was TRC which contracted with me. There, I met Dennis and John. Dennis asked me to evaluate the ecological aspects of the Brodhead Creek site. This was my first MGP site. More importantly, this was the beginning of a life-long working relationship with Dennis and John on MGP sites.
• Dave Linz at GRI was urged by his management at GRI to move forward with a program to develop protocols and guidance for the gas industry on how to address MGP sites. Management at GRI encouraged him to consider one of the larger companies known for doing entire projects “in-house”. Dave developed a Request for Proposals (RFP) that went out to these firms. But he also distributed the RFP beyond the usual suspects and the list included some smaller niche companies. One of these smaller companies was the newly-formed Atlantic Environmental who had been alerted to the opportunity through their client Jim Villaume of PP&L. Atlantic Environmental reached out to me for the risk assessment component of the work; I included Gradient Corporation in my proposal as I had established a working relationship on risk assessment with Brian Murphy who had recently Gradient. Another smaller firm that spun off from ENSR was RETEC, formed by Dave Nakles and others.
• Dave Linz had a vision on how he wanted to approach the project. First he wanted to be hands on and personally involved, sharing project management responsibility with the contractor(s). Second he wanted high-level expertise with individuals who had actual experience at MGP sites, with coal tar, and with contaminated site investigations, risk assessments, and remediation. As he looked across the submitted proposals, his vision led him to pick and choose a team of smaller companies that contained the requisite ingredients rather than a single large company. The team members included four recently formed companies led by individuals who had cut their teeth on the emerging environmental consulting field of chemical contamination: RETEC (lead by Dave Nakles), Keystone Environmental Resources associated with the Koppers Company (lead by Andy Middleton), Atlantic Environmental (lead by Dennis Unites [John Ripp would support a related effort through EPRI]), and my risk assessment firm teamed with Atlantic. With this team, Dave felt the key elements were covered: the gasification process and coal tar related matters (RETEC and Keystone/Koppers), MGP site investigation and assessment (Atlantic), and risk assessment. The firm IT was also involved early on for a segment of the work related to remediation technologies. Dave valued Dave Nakles’ project management and communication skills and so Dave Nakles became the teams coordinator/project manager. Dave Linz remained intimately involved in all aspects. The charge to the team was to develop the GRI guidance documents covering all technical aspects of assessment and remediation of MGP sites within one year.

Almost forty years later, nicely aged members of the GRI team: Dennis Unites, me, and Dave Nakles. Missing from this picture are Andy Middleton along with others including John Ripp who was key on the EPRI program.

Along with choosing the consulting team that would develop MGP assessment/remediation guidance for the industry, Dave Linz formed a Town Gas Workgroup comprised of representatives of utilities. He wanted their buy-in as well as their insights for the effort. The first meeting took place in San Francisco and Dave remembers the trip as an emotional high and low. The meeting with the Workgroup on Monday January 27, 1986 was a success and the utility representatives were receptive to Dave’s approach and eager to support the effort. As Dave traveled back to Chicago on Tuesday on January 28 he saw the news about the Challenger accident that took the lives of seven individuals including Christa McAuliffe, a teacher who had captured the imagination of school children across the country. The fusion of a joyful and a tragic event within a short window of time remain within Dave’s thoughts.

Our team accomplished what was expected. There were many meetings including discussions with the Town Gas Workgroup. We learned from each other and worked hard at this for a year. The guidance documents were produced in two iterations. The first was as a “living document”, a 4-volume series of binders two of which are shown below. The second updated iteration came out as a book.

The production of the GRI guidance reflects passion, energy, and expertise brought together through the vision of Dave Linz. This was the first major step of the team’s effort. We would proceed to an extended project we referred to as Environmentally Acceptable Endpoints. But I precede that with an acknowledgment to Dave Linz who gave form to the combination of effort, preparation, and serendipity that led to the success of these efforts and the team of experts who worked together to make it happen.

Dave Linz is passionate about what he does. He is advising organizations on research initiatives. One of his passions is painting. Reflecting on what I witnessed during the GRI program, Dave enjoys and is skilled at creating things -whether it be a technical program or a painting- by melding a spectrum of diverse elements.

Environmentally Acceptable Endpoints

As our effort to produce the GRI guidance manuals was wrapping up, some of our team members such as Andy Middleton and John Smith pushed the idea that there was a need for data. This idea was emerging in connection with remediation and clean-up levels for coal tar and associated polycyclic aromatic hydrocarbons (PAHs) in soils.

PAHs are a group of hydrocarbons comprised of two or more aromatic rings; benzene is not a PAH but is one aromatic ring. They are an environmental and human health concern because of their potential for toxicity and persistence within mixtures such as coal tars. Molecular structures for the most common parent compounds is shown below.

PAH molecular structures for “parent” PAH compounds. There are many other alkylated PAHs. PAH compounds vary in toxicity with a number of the higher-molecular weight compounds such as Benzo(a)pyrene considered to be probable human carcinogens. The lower molecular weight compounds (i.e., 2 and 3 rings) tend to be more mobile and faster to degrade than the higher molecular weight compounds. However, when present in tar source materials, all compounds can reside over extended periods of time. Figure credited to Karishma Hussain.

Land farming treatment efforts for coal tars and petroleum wastes were showing that while concentrations of PAHs and other hydrocarbons in soils were initially reduced in concentration, there appeared to be a level below which further reduction occurred only very slowly, if at all. This was considered unfortunate because the PAH residuals remaining in the soil were commonly higher in concentrations than health-based soil screening levels. One perspective on this outcome was that land farming treatment methods might not be adequate to treat PAHs in soils to acceptable levels. Another perspective was that the decrease in the rate of PAH degradation in soils reflected something else. Our team members referred to these degradation rates as fast and slow and that the coal tar and other hydrocarbon mixtures were comprised of a “fast fraction” and a “slow fraction” with respect to response to degradation. But there was another message in these data. A thought emerged that the fast fraction might be the component that results in exposure and risk as it was obviously biologically available for biodegradation while the slow fraction might be bound and biologically unavailable. (Years later, scientists working on bioavailability of chemicals in sediments would roughly interpret the fast fraction as reflecting the freely available chemicals or Cfree; this fraction was considered most relevant for estimating exposures. That concept was also supported by a commensurate reduction in toxicity. Key contributors to these concepts include Dom DiToro, Joy McGrath, Phil Gschwend, and Tom Parkerton among others).

Dave Nakles pressed for the continuation of the team’s efforts. “If we don’t do this now, we will kick ourselves for not doing it ten years from now,” he said.

Dave Linz was convinced and saw the benefits of developing this further with supporting data. He coined the phrase Environmentally Acceptable Endpoints to capture the idea that the mere presence of chemicals in soils or sediments did not necessarily mean a health or environmental risk was present. Instead, it was important to know whether the chemicals were biologically available. While the insight on the role of bioavailability had come from observations on breakdown of PAHs and coal tars in soils, a strategy would be needed to consider bioavailability with respect to human receptors as well as other environmental receptors including benthic invertebrates, fish, and wildlife. The approach would require methods to define and measure the Environmentally Acceptable Endpoints for the relevant range of human and ecological receptors. Dave Linz was successful in securing ongoing funding for this effort.

The Environmentally Acceptable Endpoints initiative involved several collaborations. First was the collaboration with academic and research leaders. While many were involved, three key people were Raymond Loehr of University of Texas, Martin Alexander of Cornell University, and Dick Luthy of Stanford University.

The collaboration with academic leaders was important for bringing knowledge and cutting research into the effort and for raising the visibility of the project. These individuals were also publishing on matters related to bioavailability, the concept at the heart of Environmentally Acceptable Endpoints.

A second collaboration was with the professional society Association of Environmental Health of Soils (AEHS) under the direction of Paul Kostecki. AEHS provided a forum for presenting information and networking with other groups exploring the issues of assessing and remediating hydrocarbons in the environment.

This latter group comprised the third collaboration and included the Department of Defense led by the U.S. Airforce, the Petroleum Environmental Research Forum (PERF) comprised of members from the oil and gas industry, and the railroads industry. Ongoing projects were led by members of this collaboration.

A fourth collaboration was with members of the Town Gas Working Group. Ed Neuhauser -a former student of Marty Alexander and a knowledgeable soil scientist- was an environmental manager for Niagara Mohawk's MGP sites. He was one of the more influential members of the group and helped guide the direction of the program. He also supported many research efforts on all aspects of MGP assessment and remediation. I had the good fortune to be part of a contingent supported by Niagara Mohawk to be sent to the Netherlands to learn about how they deal with MGP sites. The Netherlands is a leader in soil management inasmuch as soils are highly valued and detailed policy has been developed.

While these collaborations focused mainly on bioavailability issues, a related program was implemented to address the fact that hydrocarbons associated with coal tars, oils, and various products were all comprised of mixtures. Thus mixture toxicity as well as biological availability were key challenges to the assessment of risks. To help address this, The Total Petroleum Hydrocarbon Criteria Working Group (TPHCWG) was formed. My company was fortunate to play a key role within this group.

The approach developed by the TPHCWG was based on assigning toxicity values to individual compounds and fractions and using an additive approach. An additive approach was also advanced for mixtures of PAHs. The relative potency approach was developed in part through the efforts of colleagues and friends Gail Charnley, Ian Nisbet, and Peter LaGoy. The approach went through further evolution and now is the EPA’s approach for evaluating the carcinogenic risks of PAH mixtures.

For coal tars there was a parallel interest involving the direct measurement of the toxicity of coal tar mixtures in animal studies. Most of this work was led by the Electric Power Research Institute (EPRI) and involved feeding coal tars from various sources at low doses to rats. Larry Goldstein of EPRI managed this work and Eric Weyand of Rutgers was a key investigator. I kept in touch with Larry and Eric to understand how this research would inform risks of PAH mixtures associated with coal tars. An example of their published research is shown below and there have been many papers that point to the complex toxicity associated with these mixtures.

An overview paper on the EPRI-funded research on mixture toxicity of BaP and coal tars.

The Environmentally Acceptable Endpoints program yielded a number of scientific papers. However, a comprehensive guidance document stemming from the program was not produced. What was produced were ideas regarding approaches and analytical methods on how to assess the bioavailability of hydrocarbons and other organic chemicals in soils and sediments and how to incorporate these into risk assessments. These ideas mixed with similar ideas arising elsewhere were subsequently carried into myriad programs within the research arms of academic institutions, government agencies, and industries. An example is manifested by the National Academy of Sciences (NAS) report Bioavailability of Contaminants in Soils and Sediments: Processes, Tools, and Applications. Dick Luthy chaired the committee; I and others with expertise on bioavailability such as Mike Ruby and Dave Dzombak were members. I see the stimulus of thought regarding bioavailability and the exploration of practical approaches as one of the Environmentally Acceptable Endpoints program’s greatest contributions.

The matter of bioavailability of PAHs has continued through most of my career. This has included developing guidance on the use of passive samplers. One of these led by my colleague Susan Kane Driscoll with Rob Burgess of EPA is shown below.

Passive sampler procedures for estimating the bioavailable fraction of organic contaminants in sediments.

A related initiative I undertook for ESTCP with a team of collaborators and with input from all EPA regions involved developing guidance on integrating passive samplers to measure bioavailability into the management of contaminated sediments.

The bioavailability of PAHs and other organic chemicals in sediments was the impetus for the development of SediMite, an in-situ technology aimed at reducing the bioavailability, exposure, and risk of these compounds to people and the environment. My thinking about the SediMite technology began with the Environmentally Acceptable Endpoints program when at one of our meetings I heard Dick Luthy discuss the work he and Upal Ghosh were doing on identifying the role of black carbon particles for adsorbing organic chemicals present in sediments. They then explored the use of activated carbon to reduce bioavailability of PCBs in sediments. It was shortly after that that I discussed the SediMite concept with Upal Ghosh as I describe in a later story.

An effort I’d like to highlight regarding bioavailability of PAHs to humans is one led by my colleagues Yvette Lowney and Mike Ruby. These two individuals were a powerful team that initiated key bioavailability studies. With other collaborators, we assessed the science associated with understanding the bioavailability of PAHs to people via the oral and dermal routes of exposure. The abstract is shown below.

The continued MGP journey

After working with GRI and then GTI, my work related to MGP sites was almost exclusively for utilities across the country with an emphasis on sites in the east and several major utilities including National Grid, Keystone, Niagara Mohawk, Central Hudson, Public Service Electric and Gas, and South Carolina Electric and Gas. I continued to work with EPRI on broader issues affecting the electric utility industry. Through that effort I met Andy Coleman who at the time was EPRI’s manager for the MGP program. Andy is a scientist, an entrepreneur, and an educator who spends part of each year teaching at Lehigh. He is also a close friend and I’ve enjoyed giving lectures in his classes. These share the learnings from the MGP work described in this story.

Another aspect of MGP involved litigation and addressing regulatory matters. Those activities involved building relationships with environmental attorneys. One of my early cases involved working with John Voorhees who mastered technical as well as legal aspects of MGP sites and associated chemical exposure issues. Another involved working with Bill Pence in Florida on a complex former MGP site nestled within a high-end commercial marina. Finally, I enjoyed working with Greg Bibler and Ned Abelson on sites in New England. Almost all sites were located on water bodies. Waste disposal locations for purifier wastes could be further inland and there presence was the source of a number of lawsuits.

I and my colleagues at Exponent are still engaged in evaluating the risks associated with MGP sites. Our current leader on assessing MGP sites is Susan Kane Driscoll. Through a combination of effort, preparation, and serendipity we have most recently been supporting the efforts of WEC Energy Group based in Milwaukee Wisconsin. This is a working relationship that has lasted well over a decade and one where I have had the good fortune to observe the forward thinking on the part of the company. That included having us develop a flexible risk assessment framework for addressing all the various MGP sites. The development of the framework involved interactions with the EPA and state agencies to fashion an approach that was workable. Modifications were made over time as needed to keep pace with the available science and regulatory policy and the framework served as a useful starting place for discussions with new agency personnel and for addressing technical questions. I especially appreciate the leadership of Brian Bartoszek and Naren Prasad and the Project Managers at the WEC Energy Group for navigating the many dimensions of evaluating, remedying, and reusing MGP sites. While Exponent is responsible for the risk assessments, we worked very closely from the beginning with the team responsible for investigation and remedial design. This team was initially a startup company — Natural Resource Technology (NRT) — that included Laurie Parsons, Jennifer Hagen, Rick Webber, and Rick Fox; the company was acquired and the core of the team is currently part of Ramboll where we are working with new colleagues including Staci Goetz.

The continued work with WEC Energy Group involved my colleague Mike Kierski. Mike and I met when I first worked with him as a consultant while he was at Montgomery Watson. He was great to work with and eventually he joined my company Menzie-Cura. A favorite memory is when Mike and his wife Patty joined us on a bluff at Castle Hill overlooking the Ipswich River for our annual lobster and clam bake.

When Menzie-Cura moved to Exponent we were fortunate that Mike stayed with us. Mike’s presence in Wisconsin and his personal and management style contributed greatly to the development of our work relationships with WEC Energy Group and the other consulting team members for the company. Mike was a natural collaborator and brought the best people together. He was practical and amazingly easy to work with. Shortly after retiring from a long and productive work life, Mike was biking along a road near where he lived in Saulk City and was killed in a hit-and-run. We were all greatly saddened by this loss and felt for his wife and family. This is part of a note I shared with Patty Kierski that reflected a little on the nature of Mike:

Here are two things I can share about Mike in the work environment. First and foremost is his engaging personality. I discovered that while Mike exuded warmth to everyone around him, this was a Midwest way of interacting with people. As a New Yorker, I had not experienced very much of that welcoming spirit. And so, I was surprised when we had meetings and everyone spent time before “getting down to business” just talking to each other about everyday things that were happening to us. I would learn about Mike, and I would learn about everybody else that was at the meeting. It seemed everyone had to spend the time to get to know each other a little better. Someone was hunting. Someone was fishing. Somebody’s daughter — including yours — was gotten married.

Patty and family brought Mike’s ashes to the boundary waters. While there they experienced the Northern Lights. It seems very fitting.

Mike would annually take his family to visit the boundary waters. This brought him great joy and we heard lots of good stories.

Patty Kierski shared this picture of what they witnessed when they brought Mike’s ashes to the boundary waters. I believe it is the best representation of his spirit.

Thanks to Dave Linz, Dave Nakles, Dennis Unites, and John Ripp for sharing their memories of our collective MGP journey. Thanks to Sue Kane Driscoll and Andy Coleman for reviews.