When did Detroid become Chernobyl 2?
How far back to do you want to go?
It started back in the 1920s, with the burgeoning auto industry bringing people into the city and metro areas in massive numbers because a job on the auto assembly line could provide a stable, good living for even uneducated people, leading to a northward migration into the city.
This lead to a great deal of diversity starting to form in the cultural and racial makeup of the city, which lead to a racist policy of redlining that was held by the HOLC (Home Owners Loan Corporation) and FHA (Federal Housing Administration) This took place in the 1930s, under the guise of stabling the housing market after the Great Depression. In practice, it lead to black families being unable to get mortgages in the city in areas that weren't "black neighborhoods".
Because many of the homes in these redlined areas were owned by slumlords and the oversight by the city, state and federal agencies were so lax, the buildings in most of these areas were ill suited and unsafe for living in.
Which lead in part to the Brewster-Douglass projects, which were part of the programs which were the first federally funded program to build homes for inner-city African American poor. This lead to the construction of the the Brewster homes in the 1930s, and eventually the the Fredrick Douglass Towers (6 14-story high rises- build in the 1950s). However, these were also mismanaged due to corruption in the city government, lack of care and oversight, and again lead to horrible living conditions... and a center of highly consolidated urban poor.
Racism and corruption continued in the city for years and years, with various riots and uprisings, until reaching a cresendo with the 1967 race riots.
This supercharged white flight out of the city into the more affluent suburbs, serving to destroy the taxbase of the City of Detroit just as the Seventies began and the auto industry went into a major slump, leading to a high number of layoffs and further decay of the city center.
The 1980s lead to a triple whammy that further plunged Detroit into it's issues: Drugs and the "War on Drugs" a corrupt city government lead by a charismatic mayor, and the further automation of the auto industry... leading to more and more of the unskilled/uneducated autoworkers losing their very lucrative jobs.
The 1990s and 2000s saw more of the same problems, with the 2010s including the additional wrinkle of the entire auto industry requiring a bailout AND the city falling into the largest every municipal bankruptcy in history.
So, yeah. Detroit has a long complex history with multiple causes for it's slide to it's current state.
Unlike Chernobyl, which has an answer of "nuclear meltdown and it's resulting radiation.
But if I had to pick an exact date? Probably some time in the late 70s or early 80s.
