Posted especially for RMN readers who are unfamiliar with the history of this nuclear site.

Santa Susana Field Laboratory
From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Santa_Susana_Field_Laboratory

[snip]

Throughout the years, about ten low-power nuclear reactors operated at SSFL, in addition to several "critical facilities" that helped develop nuclear science and applications. At least four of the ten nuclear reactors had accidents during their operation. The reactors located on the grounds of SSFL were considered experimental, and therefore, had no containment structures.

The site ceased research and development operations in 2006. The years of rocket testing, nuclear reactor testing, and liquid metal research have left the site "significantly contaminated". Environmental cleanup is ongoing.

In 2018, a 7-year-old girl living in Simi Valley died of neuroblastoma, prompting public urging to thoroughly clean up the site.