From NJ.com:

U.S. Sen. Frank Lautenberg was taken by ambulance tonight from his Cliffside Park home after suffering a fall, his spokesman said.
The 86-year-old Democrat was conscious when he was taken to the hospital “as a precautionary measure,” said the spokesman, Caley Grey.
Grey said he did not know if Lautenberg had fallen inside the Bergen County condominium or whether he had suffered any injuries, but said the Senator was feeling better shortly before 11 p.m.
“The Senator is in great spirits and joking with the doctors,” Grey said. “He is going to stay overnight for routine observation.