A quick search said that DDT was banned nationally in 1972. I was a sophmore in college by then. Guessing that some individual states/localities had already banned it by then. I know there are other chemicals you can still use for mosquito fogging. Working in theatre technology most of my life, there are various ways to simulate fog/smoke/mist on stage. The most basic (used in all those cool old monster movies, etc) was just spraying oil on a heated surface. I think this was mostly mineral oil, which creates tiny particles that float in the air for a long time.
Anyway, last I checked, current theatrical smoke machines are just fancier versions of this, using either mineral oil or proprietary recipies. Then there are something called "haze machines" which slowly churn out a fine mist of little particles that hang in the air (the old ones used mineral oil, some of the new ones use glycerol, which is plant-based). After you run these for a little while, they create a pretty uniform haze that makes light beams looks cool. There are also "fog machines" that simply use dry ice dropped into hot water to create a dense fog that hugs the floor instead of rising into the air. To further confuse things, some people call all three of these technologies "fog machines" but they're actually very different.
During my years at Opera Philadelphia, I was able to negotiate the use of haze machines and dry ice fog machines with the singers' union but they absolutely refused to accept the use of any smoke machines! Other kinds of entertainment have their own unions and rules, but are typically more permissive while still setting limits on the use of smoke machines.
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