Fog Machines

Fog machines are a relic from my childhood in the sixties—a memory as unrelenting as the heat and humidity of summer in Mississippi. Around supper time, as the sun began to slide down the horizon like a riff, aging pickup trucks would emerge like mosquitoes. Soon, the aerosol generators bolted to their beds began to burn oil, forty to eighty gallons an hour, and belch insecticide fog. The cloud was thick and white, like the cumulus formations that skidded across the sky during the day under our watchful eyes from our positions flat on our backs on the grass. But the cloud from the fog machine was within our grasp. We had only to chase it to find ourselves inside. And so, children were excused from the table, released into the approaching night. We ran then, down the street behind the machine, as if it carried our very dreams and hopes. Unaware of the danger.


What are fog machines?


Truck-mounted thermal aerosol generators used in mosquito control programs produce a highly visible insecticide fog that moves across open spaces, killing mosquitoes in flight as air currents move it.

Source:  http://www.health.state.nm.us/erd/HealthData/documents/Equipment_000.pdf

What is the history of thermal foggers?


Viewpoint:  Are We Just Power Mad?  By Robert Ward – Winter 2000 Issue of Wing Beats

…Stroll down memory lane with the venerable thermal fog machine, be it a TIFA, LECO, Dynafog, or any other of those hot smelly "smokers" belching up to eighty gallons of fog material an hour. …here came ULV. No more fireballs, greasy streets and cars, or blinded drivers (either yours or the public). 


Source:  December 2007 interview with Robert Ward – retired Manager, Polk County Mosquito Control, Bartow, Florida


Q:  Approximately when were thermal foggers used in the U.S.?

A:  The thermal fogger was the sprayer of choice in the early 1960s.

Q:  What did the thermal foggers look like?

A:  Pickup trucks were used – a cab and chassis. The sprayer was mounted on a plate and bolted on the cab and chassis. The nozzle mechanism cost $500, which was very expensive back then.

Q:  Where were the thermal foggers used?

A:  Throughout the U.S., but concentrated in California and Florida and along the Gulf Coast.

Q:  How frequently, and during what parts of the year, was spraying typically done?

A:  This varied regionally, but in Florida it was from April to October and once per week on average. In the 1960s, when there were encephalitis outbreaks, an area might be sprayed several days in a row.  Many programs sprayed all night. Others sprayed for the first 2-3 hours of darkness and the last 2-3 hours before daylight.

Q:  What prompted the switch from thermal to ULV foggers?

A:  A prime impetus for the switch was the fuel crunch of the 1970’s. ULV did not require oil, whereas the thermal foggers used 40 or 80 gallons/hour.

Also, the thermal foggers were dangerous.

  • The burn unit fired off gasoline with a sparkplug.  A 16-horsepower engine turned the blower and pump.  The thermal fog nozzle was nearly “superheated” – cherry red when not spraying.

  • The fog was so dense that the front end of the vehicle would disappear. And the oily pesticide spray smeared windshields. Both things contributed to accidents.  One of the most famous involved actress Jane Mansfield. 

  • Occasionally the thermal foggers threw fireballs.  This could happen any time during the night of spraying, not just at startup.  (Think kids chasing the trucks.)

How does the fog machine serve as a metaphor?

The metaphor is a compound one. Not just “fog” – confusing, mysterious, obstructive. Not simply a “machine” – rhythmic, controlled, organized. But a “fog machine” – poisonous, seductive, pervasive, deadly, distorting, relentless.

I relate the metaphor to the mission of the William Winter Institute for Racial Reconciliation which describes prejudice as “systemic and institutionalized.”


While her friends turned the rope, Joan jumped and jumped, not noticing the fog that crept up the street, overpowering the sweetness of the azaleas in Sally Ann’s yard. Only when Cindy suddenly stopped looping the rope did Joan hear the old truck clanking down the street on its mosquito-control mission. She turned to see the lumbering white pickup with the machine bolted to its bed. The nozzle burned red-hot and belched thick clouds of insecticide.

“It’s the fog machine, y’all. C’mon!” Cindy yelled.

Like mice after a piper, the girls threw down the rope to trail the billowy stream. They chased it, fading in and out of view whenever a slight breeze took the fog in unexpected directions.

Joan ran with them, as if she were riding one of the thick white clouds that skidded across the sky, delighting in the feel of being inside.

But then C.J. had to ruin it all. “We’re losing the light, Joan,” she called. “It’s best we head on back now.”

Joan turned to go, but one of the girls bumped into her. What if it was Cindy? She couldn’t just run on back, not after Cindy had already made her feel like a baby because C.J. had tagged along. So she ran on with her friends, until the truck rounded the corner and left their street. Only then did she emerge from the cloud, walking backwards toward home.

“Goodbye,” Sally Ann called to Joan. “It sure was fun using my new jump rope!”

Joan waved, and as she finally followed C.J. and Andy, she was glad for the falling darkness that hid the slight flush on her cheeks. Embarrassment was all it was, she told herself, though she knew it was more. Satisfaction suffused with shame, over learning what to do to fit in with her friends. And as much as C.J. knew, that was something she would never understand.


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