I have pointed out the 1990 date in reference to MIT's building 20, which was a temporary building granted a permit with specific language:

"We received the decision for the Cambridge Board of Appeal on May 5, 1943 allowing us to construct the building as a war measure, the life of said building to be for the duration of the war and six months thereafter."

It lasted more than six months after the end of the war. The 1990 end of the war.