A man — we’ll call him “Subject No. 1” — had a clear plastic pipe stuck into his mouth with his lips sealed around it, while the diesel exhaust from a parked truck outside the gas chamber was mixed with particulate matter and pumped straight into his lungs. The pumped mixture level was 135 times the mean diesel truck emissions exposure in the United States.

Scientists Andrew Ghio, Jon Sobus, Joachim Pleil and Michael Madden, with laboratory director Wayne Cascio, administered this toxic mix of diesel and particulate matter to 41 people. In all, they gassed 81 subjects with various mixes of diesel, particulate and ozone in five different experiments — tagged with the science fiction-like names Omegacon, Xcon, Kingcon, Depoz and Lamarck.