“As a former Navy firefighter.”
When my career Navy father was stationed at Great Lakes, the early 1950s.
Occasionally he would take us to a graduation ceremony(?), where they had huge open-top tanks with fuel oil burning inside. They had bleachers set up at a safe distance.
A team would line up outside feeding hose to the front and others spraying water on the front of the team, and they would enter the tank and extinguish the flame!!!
Amazing.
Years later I learned from Navy friends that the EPA SHUT IT DOWN!
It was replaced with a smaller set up inside a containment with air scrubbers to clean the smoke.
They said they still do it.
Nothing I would want to be involved with, even when I was young and crazy.
I've been through the "old school" shipboard firefighting trainers that burned fuel oil, as well as the new ones that burn propane. It is like night and day as far as the heat intensity, even wearing a full firefighting ensemble. With the fuel oil fire, you actually felt like you were in danger, despite knowing it was a trainer. You believed that if you screwed up, someone could die. Kind of like the difference between live fire and a MILES trainer.