Levine Cava said there are 210 people searching the rubble at the same time, adding the crews are working 12-hour shifts.
Seriously what good is 12 hour shifts? It's hard work, and it's hot outside.
They claim that there are many groups on standby, that haven't gone in. So let them go in.
After 6 hours, go get some rest and air conditioning, and let the next fresh group in.
Or is it like
@jj1000 had said, that there are a lot of firefighters earning overtime..