The sound was so loud it apparently set off car alarms.

According to multiple reports on Reddit, a loud 'boom' was heard in Schenectady shortly after 8am Tuesday. The blast was also heard in parts of Scotia and Glenville. 

One report said the explosive sound sent people running to the windows at an office on Broadway, to find the noise had set off several car alarms. 

Loud boom set off car alarms near Broadway in Schenectady?
byu/metrogoldwyngayer inAlbany

The Times Union reports firefighters were at the Tri City Recycling plant later in the morning and the boom may have come from a small cylinder that exploded. 

No injuries were reported.