Some strange dirt on PG&E dug up by the Chronicle: For the last four years, the utility has been buying out multi-million dollar homes in the Marina to remove chemical contamination from toxic waste in their yards, the result of fuel manufacturing plants from almost 100 years ago.

"For a number of months, they would systematically shovel out 8 feet of soil and then bring in new soil,” a neighbor recalls to the paper. In total, PG&E has bought eight homes, one which has two-units, and is in the process of buying a ninth. Two of the homes were resold after the dirt-laundering was done, and others were rented back to their former owners. From nine other nearby houses that didn't want to sell to PG&E, the company still went through the process of swapping their yard soil, and the utility did the same at a former Bay Street gas station, pictured above.

Regulators overseeing the work say the chemicals pose no danger to public health, buried as they are underground. However, there's concern that future development could expose them, hence the laborious steps taken by PG&E. The gas station site, for example, is being developed for 28 condos, as Hoodline reports.

PG&E once had 41 similar fuel plants in California, and as it's performed tests at sites elsewhere, it's clear the company thinks some sort of action at these locations is necessary. All the homes are in the area of two small plants that manufactured gas in the late 1800s, operations that were damaged in the 1906 quake and demolished. Residual chemicals such as benzene and naphthalene, which can cause cancer, were buried with their remains.

One former Alhambra Street property owner who sold his home to PG&E, Dick Frisbie, thinks the utility downplayed the presence of the chemicals. Workers on his property recovered a serious haul of coal from just three feet below ground, he claims, while PG&E had told residents the contamination was much deeper, at 18 feet below the surface. PG&E disputes this, telling the Chronicle that Frisbie is wrong and that they've always told residents the contamination is within the top 10 feet of soil.

“You could just smell them by holding them up,” Frisbie told the Chronicle. “That changed everything with PG&E, because it turned out all the information they had given us was bogus.”

Another homeowner who sold to PG&E, Dan Clarke, joined forces with the San Francisco Herring Association — who believe the fish could be affected through groundwater entering the Bay — to sue PG&E. An interim settlement was reached in 2015, and PG&E will continue testing in the area with a report due within the year. Other homeowners are also irritated that, after PG&E's work is done, their homes will lose value — the contamination history will be added to their deeds.

Elsewhere, in a much less hush-hush episode involving PG&E, the utility is debuting court-ordered TV ads that recall the San Bruno gas pipe explosion of 2010 and apologize for the incident, in which it was convicted last summer. “On Sept. 9, 2010, PG&E learned a tragic lesson we can never forget," go the short, contrite TV spots. Here's KRON 4 with those.

Related: Now PG&E Wants Its Conviction Thrown Out In San Bruno Blast Case