MacRae Quoted in Press Herald Article on Portland Gas Smell

Jean MacRae, an associate professor of civil and environmental engineering at the University of Maine, was quoted in a Portland Press Herald article about a rotten gas smell that came from construction work under the Casco Bay Bridge and spread into downtown Portland. According to the article, the smell was most likely from mercaptan, a chemical that’s added to natural gas to make it smell. Mercaptan is harmless and dissipates quickly in the air, the article states. MacRae said the chemical is often confused with hydrogen sulfide, which smells the same but is a much stronger and more dangerous chemical. MacRae said it’s also possible the smell came from natural substances in the soil breaking down slowly until they were exposed to oxygen, but she doubts enough organic material has built up at the site for that to be likely, the article states.