New York Codes, Rules and Regulations
Title 21 - Miscellaneous
Chapter XXIV - The Port Authority Of New York And New Jersey
Subchapter E - World Trade Center
Part 1290 - World Trade Center
Section 1290.20 - Acts or omissions resulting in filing of liens prohibited

No person shall do or omit to do anything which may be ground for the filing of any mechanic's or other lien against the World Trade Center or any part thereof. Nothing herein shall be deemed to be a consent by the Port Authority to any such lien or the filing thereof or any implication that such lien would be valid or enforceable against the Port Authority or its property, but if such lien is filed, notwithstanding that it may be groundless or unenforceable, the Port Authority may take such steps as may be required to remove it including payment of any debts alleged to be owed by any person and such person shall pay the Port Authority the Port Authority's cost thereof upon demand.