The easiest way to explain this is fees and fines that are placed upon individuals that don't pay their employees' tax withholdings to the IRS.
Here's some background info...
Those taxes that take a nice bite out of your paycheck (Federal, Social Security, Medicare) are not being taken out by the IRS. Your employer withholds these amounts for you. (Don't get all sentimental. They're required by law to do this.) Then, your employer pays those taxes to the IRS quarterly. These quarterly taxes are called "payroll" taxes, also known as 941's.
Here's where the trouble comes in.
What if your employer does not pay these taxes to the government? Big trouble. Not only does the IRS consider this stealing from them, they also consider this stealing for you, the employee, as well. Even worse is when you file taxes and the IRS pays you money in a refund... money the IRS never received from your employer in the first place. Now, as an employer, you've stolen from two people and put the IRS out of some dough. You better believe they're coming after you.
But who will they come after?
This is where the IRS becomes ruthless. "Who" you ask? Anyone involved in payroll is the answer. And they can assign the Civil Trust Fund Portion (unpaid payroll taxes) and Penalties (fines) onto anyone in any fashion. It does not have to be one person or the big wig. It can be anyone they get their hands on.
Act quickly. Find a reputable firm to represent you because these matters get tricky. Research thoroughly who will be doing your bidding and cooperate.
Items on the Trust Fund Recovery Penalty