it has now been banned in scotland. it is being removed from england this year. there is movement to ban it in europe by 2026. joanne: how common in the u.s. is that switchover? dr. sherman:dr. sherman: we don't have data on that. . i can tell you anecdotally it is becoming more common. we saved $1.2 million just on our flagship hospital 11 years ago by getting rid of this. the other challenging gas as nitrous oxide. it is a different type of gas. it types through the hospital walls. a lot of gas is lost in the connections between -- joanne: up to 80%. dr. sherman: actually more than 90%. getting away from the pipes and going to tanks at the point of use, you can eliminate 95% of that. joanne: let's go to dan. in your institution, you were the change agent. a small group of colleagues. the example of the nurse i was talking about. i did not know her when i was writing about this. i just met her on the phone this week. people like you are how a lot of change beginning in the health care system. and you are not as far along as yale and you are not as far along as t