Sources said preliminary tests indicated the envelopes contained baking soda. Officials deemed the situation non-hazardous.
The letters were delivered to :
The Carlstadt Police Department says they got a call from the Econo Lodge at 11:30 a.m. saying someone going through the mail opened a letter with a suspicious powder on it.
Calls from other hotels started coming in shortly after.
Police were able to locate the mail carrier where the letters originated and intercepted additional letters headed to a Hampton Inn and Holiday Inn Express in Carlstadt that were never delivered. Other letters may still be out there.
" Notices went out to members statewide. There could be more letters out there. Not just in the area of MetLife Stadium," Joseph Simonetta Executive VP of the NJ Hotel and Lodging Association said. "They are encouraging everyone to not to attempt to handle or alter any suspicious envelopes and to immediately call the authorities."
Hackensack University Medical Center received a number of people for evaluation because they came in contact with the letters, but a hospital spokeswoman said there were no reported illnesses or injuries.
Police were also called to former Mayor Rudy Giuliani's consulting firm near Rockefeller Center after a worker opened the suspicious letter addressed to Giuliani around 10:30 a.m. Friday, police said. Eight mailroom workers underwent decontamination as a precaution.
A representative for Giuliani's firm did not immediately respond to a comment request.
Police say preliminary tests showed no threat from the powder found in that letter.