City environmental officials who inspected the 42-year-old sports and concert hall Tuesday afternoon gave it a clean bill of health.
Debris dislodged during a cleanup of an attic space had triggered two air quality detectors, but subsequent testing revealed that the particles did not contain asbestos, city officials said. The finding came too late in the day to save Tuesday night's Knicks game against the Orlando Magic, which had already been postponed.
Mayor Michael Bloomberg said Wednesday that even though there was no health risk, the arena's operators deserve credit for putting safety first.
"If they made any mistakes, they were mistakes in the direction of being cautious and they should be commended for that," he said. "It turns out that our Department of Environmental Protection is very satisfied that there was no asbestos there. There were no risks, and if we had more time before they had to make a decision on the game, perhaps they wouldn't have even canceled the game."
A spokeswoman for Madison Square Garden declined to answer questions about the mishap or comment on the timetable for a return to normal operations.
The Knicks are scheduled to play the Washington Wizards at the Garden on Friday.
The arena is in the midst of a major renovation that will revamp the seating, add new luxury suites and create a new entrance and new public concourses. Much of the heaviest construction has been scheduled for summer months, but some work is being done year round.
Work is expected to continue through the 2013-2014 NBA and NHL seasons.
It is unclear how much of that overhaul involves abating asbestos, or whether that kind of potentially hazardous work will be confined to the off-season when the building is closed.