I’m retired but used to work in aerospace, we built parts for the F22 and many other planes. Most of the workers were Hispanic immigrants that couldn’t read in any language. We became aware of it when one of the workers was asked to take a measurement with a digital caliper, he walked away to ask another Hispanic what it said. We offered English and reading classes, but they would not come.
We decided to give tests to see if these people were qualified to do their jobs and found out the women were trading sex for the answers.
The bathrooms were filthy, they would wipe their butts and throw the used toilet paper on the ground because that is what they did back home. They would take their feces and wipe it on the bathroom walls or mirrors. They would take cups of piss and set it on the bathroom stall doors to catch their friends.
It got bad enough that we had to install cameras on the outside of the restrooms and constantly check the restrooms.
The Asians, mostly Vietnamese, stood on the toilet seats and squatted, we were constantly fixing toilet seats.
I have a relative in the trades who tells me stories of Mexican workers daily totally trashing with excrement all over the inside of the provided outdoor toilets where it sometimes would make tradesmen puke.