What lurks beneath the asphalt in the Oroville parking lot on Montgomery and Huntoon streets?
PG&E is voluntarily working in conjunction with the California Department of Toxic Substances Control to find out.
The property, which is now used as the parking lot for the Oroville Civic Auditorium, used to be a manufactured gas plant.
"Companies like PG&E would actually manufacture gas from oil, coal and other materials to provide lighting and heat in homes," said PG&E spokesperson Paul Moreno.
It operated between 1878 and 1927, during which time PG&E purchased it. The plant was eventually dismantled. PG&E sold the property to the City of Oroville in 1964.
But the substances from the manufactured gas have been sitting there for more than a hundred years, and there is evidence that contamination is there, although not necessarily toxic.
"Yes, we have done sampling," Moreno said. "And we're doing additional sampling now to determine the extent and how much clean-up will need to be done."
Geologists and environmental consultants have been drilling for two weeks, collecting soil samples to see the levels of contamination. The analysis will determine whether soil needs to be removed and replaced.