© 2022 IEEE.In the smart emergency detection systems, which automatically detects emergencies and disseminates proper alerts to the citizens and local authorities, accuracy and security is significant concerns. To overcome these concerns, we propose a blockchain-based open emergency alert system, namely EmergencyBlock. Our envisioned system has decentralized structure helps the system's availability during the crisis situations that cause high load. Nodes in the system have a shared public ledger that holds emergency event data and no other data that may create privacy concerns. Because of the system's public nature, the blockchain is used to prevent false alerts by protecting the integrity, and also asymmetric encryption is used to protect the confidentiality of the system.