By Walter Mugdan
In 1792 the Scottish engineer William Murdock pioneered the process of commercial coal gasification – that is, turning the solid lumps of hard, black mineral into gaseous form. Murdock, a colleague of James Watt (of steam engine fame, not the former U.S. Secretary of Interior), heated coal in the absence of air, converting most of the coal to a gas similar to the natural gas that many of us use today heating and cooking.
Murdock’s purpose was to generate gas that could be used for lighting. Within a few years gas lighting became common in factories in Britain. By 1814, gas streetlights were being installed in London, and by 1819 close to 300 miles of pipe had been laid in that city to supply some 51,000 burners. In 1816, a Murdock licensee, the Baltimore Gas Company, started the first coal gasification operation in America, also primarily for use in lighting. For many decades, coal gas was the dominant fuel for indoor lighting, and for nearly a century it was dominant for urban street lighting.
More than 1500 gasification plants (known as “manufactured gas plants” or MGPs) operated in the U.S. in the past. It was expensive to build the pipes and other infrastructure needed to convey the gas to homes and streetlights, so these plants were built in the midst of the densely populated urban areas near where the gas was used; New York City alone had several dozen. The last MFG plant in New York State closed as recently as 1972.
Gaslight was quite beautiful – even romantic – and, of course, an amazing improvement over candles and oil lamps. But coal gasification was a very messy business, leaving tarry residues loaded with what we now know to be toxic chemicals. The coal tar wastes were routinely dumped on the ground. Because the coal tar never really hardens, it tends to ooze its way down into the ground until it hits some obstruction (like bedrock), and then it moves sideways. Because MGPs used lots of coal, most were built next to a commercial waterway for ease of delivery. Consequently, those waterways are now often contaminated by the coal tar.
There are plenty of coal tar sites on the federal Superfund list and comparable state lists of contaminated sites. In New York alone there are some 300 coal tar sites on the state’s hazardous waste site list. (Nearly 200 of these have been or are being remediated.) There were no less than 3 MGPs along the short 2-mile length of the infamous Gowanus Canal in Brooklyn, which contributed to contaminant levels in the canal mud that are measured in parts per hundred (rather than the usual parts per million, billion or even trillion).
Coal gas eventually gave way to electricity as a means of producing light; and natural gas replaced coal gas for heating and cooking. But the mess left behind by the MGPs remains a huge problem, requiring billions of dollars in cleanup costs.
About the Author: Since 2008 Walter has served as Superfund director for U.S. EPA Region 2, managing the region’s toxic waste cleanup, emergency response and brownfields programs. For the previous six years he was director of the region’s air, water, hazardous waste and environmental review programs. He joined Region 2 in 1975 as a staff attorney doing air pollution enforcement work. From 1991 to 2002 he held various supervisory positions in the region’s legal office, culminating as Regional Counsel. In his private life he heads a small, local conservation group in northeast Queens. He enjoys bicycling, kayaking and hiking; and since 2010 he has been moonlighting as an Executive Producer (read: source of funding) for his daughter’s nascent career as an independent film maker.