Poisons from the past

In 1874, Chico residences and businesses got hooked up to gas lines for the first time, allowing them to use gas in their homes for lighting, cooking and heating. What they didn’t know was that the convenient new service would leave a legacy of pollution that has lasted to this day.

The gas was manufactured at a plant at the southeast corner of Orange and Second streets, on what was then the western edge of town. The plant used a variety of materials, including coal, shale and pine pitch, as feed stocks, but mostly it used crude oil to make the gas.

Then, as now, the railroad ran just a few yards west of Orange. Trains stopped at the corner, and workers unloaded oil into a sump, or pit. It then flowed through a pipe that ran under the street to the plant, where it was stored in a 12,000-gallon underground storage tank before being processed and made into gas.

The tank was made of wood, so it began to rot over time. The sump also leaked, apparently. And the process of creating gas from coal and oil produced residues consisting primarily of lampblack (soot) and tars. Chemical compounds associated with the lampblack and tars include polycyclic aromatic hydrocarbons (PAHs), total petroleum hydrocarbons (TPHs) and, to a lesser extent, volatile organic compounds (VOCs). All are quite unhealthful.

By 1928, when natural gas was brought to Chico and replaced the manufactured gas, the ground and shallow groundwater in the area had become polluted with this alphabet soup of toxic substances. By then the utility company, like so many others, had been swallowed up in the series of mergers that culminated in the creation of the Pacific Gas and Electric Co. in 1905.

This year, 132 years after the gas plant began operations, PG&E is about to begin cleaning up the site—at an estimated cost of $1 million. Beginning in early July, backhoes and dump trucks will be working the area, digging out and removing 800-1,000 cubic yards of contaminated soil. That’s about 100 truckloads, said Duane White, of the state Department of Toxic Substances Control (DTSC), who is the project manager.

Most of the plant was dismantled by 1930, and today only the former generator building remains. Most of the site is used as a PG&E substation, and the building is used for maintenance work. PG&E has known about the pollution for many years and has put in a number of monitoring wells to track it. Fortunately, the toxins haven’t moved much, nor have they seeped into the deeper aquifer below, from which Chico gets its drinking water.

The most polluted area is between the street and the warehouse building. That’s where the underground storage tank was located. Diggers will have to go down a full 25 feet to clean out the toxins there. That’s 10 feet below the water table, so it won’t be easy, said White, which is part of the reason why that job won’t be tackled until next summer.

There just “wasn’t enough time to do the whole thing” this summer, White added.

This summer crews will focus on the site where the old sump was located, between Orange Street and the railroad tracks. The land is now owned by Chico State University and used as a parking lot. The goal is to clean it up before students return in late August, he said.

The toxic soil will be trucked to a hazardous-waste-disposal site. After being dug up, it may be stockpiled on the site for up to 30 days. If so, it will be sprayed with water and/or odor-suppressing agents and covered with plastic to prevent dust and odors from spreading. Excavated areas will be filled with clean soil.

Still, people walking by may notice some smells. Overall, though, the project poses no threat to health, White said.

DTSC has tried to inform neighbors of the cleanup plans, Carol Singleton, the department’s public information officer, said. However, it’s “almost impossible” to notify everyone who might be affected through individual mailings, she explained, so media stories such as this one are important to getting out the word.

PG&E is accepting public comment on its remedial-action plan for decontaminating the gas-plant site at Second and Orange streets through June 29. Copies of the plan are available at Chico State’s Meriam Library and the Chico branch of the Butte County Library, Sherman and East First avenues. See www.envirostor.dtsc.ca.gov for more info and to comment online.

The site has nothing to do with the underground tank discovered in 2003 on a former PG&E yard that is now part of the university campus. (See “Mystery tank"; CN&R; Oct. 9, 2003.) The 32-foot-long underground tank turned out to contain nothing more serious than gravel and was dug up, reported Joe Wills, the university’s spokesman.