The registered emergency rooms are catalogued on the medicare website (medicare.gov). The government has a list of all the emergency rooms in the USA. They also do a survey of each hospital periodically to keep there data up to date.

Unfortunately, these updates aren't in real time. I'm hoping I can provide people live data through my app through a feedback/reporting mechanism. It took a fair bit of time to extract all the data available and I had to do some aggregation myself.

The app doesn't yet include a notification centre widget but that's a great idea! I'm putting that on the list of potential feature adds :). Thank you!