The ambiguity of the command system is still the main challenge during the activation of health cluster coordination. It begins with the unclear division of tasks, communication channels that are not yet optimal, and do not have an alternative plan. This study reported the management of health cluster coordination posts during the disaster of Mount Semeru Eruption, in December 2021.

This study was a case study of qualitative research methods, data collection was carried out by observing the health cluster operation of Lumajang District Health Office (DHO) and supported by an analysis of health cluster activation policy reviews.

Resources to manage health clusters were limited due to a lack of staff knowledge in health cluster management. Therefore, the head of the Lumajang DHO appointed the Office Secretary as the health cluster coordinator. The Head of Referrals Health Services is the emergency medical team focal person and the Head of Health Promotion is the spokesperson. East Java Provincial Health Office, Ministry of Health, and Disaster Task Force of Faculty of Medicine UGM assisted in the management of health cluster post operations. Then, assisting was concerned with the most fundamental thing in facilitating health clusters such as establishing an organizational structure based on the incident command system approach as well as mapping the capacity of existing health resources on the field to visualize the geographical situation of health service capacity and emergency medical teams distribution.

Although located in prone and high-risk or periodically eruption areas, the staff still have a low capacity in disaster health management. Thus, capacity building in the pre-disaster phase is highly required in the management of health clusters and emergency medical team coordination by the mandate of the Ministry of Health Regulation.