A ham radio operator's recording of radio transmissions made by New York City firefighters during the morning of September 11 offer a glimpse of the dangers emergency personnel faced while confronting the World Trade Center terror attack.

The scanner recording was made by a California ham radio operator, who taped a variety of transmissions and has now posted them on the Internet.

The recording begins shortly before 10 a.m., a little more than an hour after the first plane struck the north World Trade Center tower, and approximately 55 minutes after the second plane struck the south tower .

The recording begins with a dispatcher reciting a list of FDNY engine companies that are on their way to the scene. The collapse of the south tower is reported by an emergency crew member about two minutes into the recording.

At about the 16:30 mark are several reports of NYPD officers trapped in various locations around the site.

More than 300 firefighters and EMTs, as well as two dozen NYPD officers and three dozen Port Authority officers, were killed in the collapse of the buildings, making it the nation's worst-ever loss of life by uniformed personnel.