White powder was mailed to businesses near MetLife Stadium, the site of Sunday’s Super Bowl in East Rutherford, N.J., prompting an investigation Friday by the FBI and other law enforcement. A federal law enforcement official said one of the envelopes contained baking soda, the Associated Press reported.

White Powder Discovered at Multiple Hotels Near Super Bowl Site

This aerial photo shows MetLife Stadium in East Rutherford, N.J., on Thursday, Jan. 30, 2014. The NFL’s Seattle Seahawks play the Denver Broncos on Sunday at the stadium in Super Bowl XLVIII. (Image source: AP)

Preliminary tests showed no threat from white powder also discovered in a letter sent to former New York City Mayor Rudolph Giuliani’s company in Manhattan, New York City police said.

In New Jersey, the suspicious mailings went to at least five hotels, Carlstadt Police Detective John Cleary said.

Hackensack (N.J.) University Medical Center received several people for evaluation after they came in contact with the letters, but a hospital spokeswoman told the AP there were no reported illnesses or injuries.

The federal law enforcement official, who wasn’t authorized to comment publicly and spoke on condition of anonymity, said powder from one envelope tested positive for baking soda. It’s not clear where that letter was sent.

The mailings arrived at an Econo Lodge in Carlstadt, a Homestead Inn in East Rutherford and a Renaissance Inn in Rutherford, Cleary said. Investigators intercepted additional envelopes from a mail truck before they reached a Holiday Inn Express and Hampton Inn in Carlstadt, he said.

Police were called to 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 from the AP.