The plant has been around since at least the 1970s. At the time it likely was on the edge of town, but through 50 years of urban sprawl, the town grew around it.

It may be even older than that. My source for the age of the site is this 1970 NASA ALSEP supplier list (from the moon program!), which lists the address as an approved manufacturer on page 38: https://www.lpi.usra.edu/lunar/ALSEP/pdf/31111000671279.pdf

The actual site of the tank is 33.78356416377991, -117.99993897629278 [1] - its in an industrial park, and its not a large scale chemical manufacturing facility.

Its 'light manufacturing' for a company that makes custom formed acrylics for aerospace.

https://www.google.com/maps/place/33°47'00.8%22N+117°59'59.8...

That area has dozens of aerospace manufacturers, building up since before WW2. People wanted to live close to work. There are lots of homes and commercial areas and industrial parks are tightly mixed together.

Source: I’ve worked in aerospace in Orange County.

Because greater Los Angeles is the USA's (post-)WWII aerospace hub disguised as a megacity and cultural production center? All sorts of folks spent the 40s-00s (scientifically) blowing stuff up in the hills, and manufacturing the resulting products down in the basin and points south. Those businesses needed labor, which needed nearby housing, and here we are.

It should have been in the disclosures for all the home purchases at least, but renters don’t get those (maybe they should?)

Imagine how often this situation lie this would be happening without institutions like OSHA or the EPA.

Stuff like this happens in Texas on a fairly regular basis, but it rarely ever makes national news.

As someone whose childhood home is in the evac zone ... It's a bit crazy I was living in this neighborhood my entire childhood just waiting for this to go boom

That being said California is very industry friendly and all the stuff about overregulation is from people who don't get California.

Doesn't that mean they can bike to work there?