People assume automatically that this is general law, but consider how such a law would be enforced. It would be unworkable. You'd have to define levels (trauma) of services, nature of what is required--and these are left to the boards of hospitals.
Now--the ER is a big money-loser even without the problem of liability insurance. Under better circumstances than is seen in PA, hospitals lose 40-60% on every patient in the ER. But it IS law that an ER see and evaluate all comers, and the ER usually ends up treating all comers, too. Add to that that illegal aliens know this, and use the ER. The pressures to close these departments are staggering.
So, why keep any open?
It'll amaze you, the answer. Because the boards recognize that such a service is part of their duty to the community, part of their mission as a hosptial, part of the essential identity of what they are and what they do.
So when you want to moan about the long waits and grumpy nurses--remember they could just shut it down.
Part of me really wishes they would, that Atlas would shrug.