While hospitals are generally noisy environments, nowhere is the pandemonium greater than in an emergency department, where there is constant flow of patients, doctors, nurses, and moving equipment. In this noise study we collected 24 h measurements throughout the adult emergency department of Johns Hopkins Hospital, the top ranked hospital in the U.S. for 16 years running. The equivalent sound pressure level (Leq) throughout the emergency department is about 5 dB(A) higher than that measured previously at a variety of in-patient units of the same hospital. Within the emergency department the triage area at the entrance to the department has the highest Leq, ranging from 65 to 73 dB(A). Sound levels in the emergency department are sufficiently high [on average between 61 and 69 dB(A)] to raise concerns regarding the communication of speech without errors--an important issue everywhere in a hospital and a critical issue in emergency departments because doctors and nurses frequently need to work at an urgent pace and to rely on oral communication.