Simplify the following text for a Grade 10 native English-speaking person.
Original: UCC also maintains that this route was not possible , but instead alleges water was introduced directly into the tank as an act of sabotage by a disgruntled worker via a connection to a missing pressure gauge on the top of the tank .
Simplified: UCC also maintains that this route was not possible , and that it was an act of sabotage by a `` disgruntled worker '' who introduced water directly into the tank .