Electric bus manufacturer that Zions National Park was testing files bankruptcy.
Zions still don't have EVs, and the propane buses are getting old.
Let's get Zions to replace the buses with new Propane buses and clean the air.  

https://techcrunch.com/2023/08/09/what-led-to-ev-darling-proterras-bankruptcy/

Check out document Page 43 pdf page 53 of the study from NREL that shows EV Test Bus produces more SOX and NOX than 24-year-old propane bus
https://www.nrel.gov/docs/fy21osti/78012.pdf