Technically the term chemical burn doesn't indicate severity, just that you got in contact with a corrosive material which had an effect on your skin. My guess would be someone got lime/cement powder on themselves and reported it as a chemical burn. They could have also been dissolved alive in an acid bath, but the size of the fine and the fact propublica doesn't say what happened suggests it was minor.
I derived my opinion by reading the article, noticing there was no description of the burn, and then noticing the incredibly small fine and relatively relaxed attitude by regulators. If you'd read my comment again I didn't say it was a cement burn, just that that is an example of a mild burn. The real irony is if it was just a curing accelerant, then it was an incredibly mild burn, and you're still wrong.
