How does a HazMat company/driver find SafeHaven locations?

Im a couple days away from taking my HazMat endorsement test. Am planning on getting hired on by a local fuel-company, but i got bored and hopped on a loadboard to look for HazMat loads. Im not currently planning on doing longer-haul (like OTR), but i got curious;
Where/How does a HazMat trucker and/or HazMat carrier find SafeHaven locations? Is there a site that lists them? Maybe a trucker-map app that shows the SafeHavens? Or would I need to call the FMCSA / PHMSA / county sheriffs?

 

DAT app on my smart-phone

 

Was looking into starting up my own trucking-llc; When i created my DAT-account, i put that business-info into the DAT-system and just left the Authority-number blank. Seems like i have limited access to their system (i cant see shipper-/receiver-info, other than pick-up & drop-off cities & occasionally the rate-per-mile).

 

I'm a bit ignorant on all this myself, but I think that HazMat loads can park off-street as long as the driver or a co-driver stays within 100ft, and they maintain a clear line-of-sight with the load...also cant park within 300ft of a tunnel and cannot park near open-flames / heat-source