Approved by the Infrastructure and Research Policy Committee on February 27, 2026
Approved by the Public Policy Committee on March 20, 2026
Adopted by the Board of Direction on July 21, 2026

Policy 

The American Society of Civil Engineers (ASCE) supports a unified set of definitions for the concepts of critical infrastructure, hazards, multihazards, and resilience. ASCE encourages the adoption of the following definitions:

  • Critical infrastructure includes systems, facilities, and assets so vital that their destruction or incapacitation would have a debilitating impact on national security, the economy or public health, safety, and welfare. Critical infrastructure may be regional in location or impact and could be built (such as structural, energy, water, transportation, and communication systems), natural (such as surface or ground water resources), or virtual (such as cyber, electronic data, and information systems). 
  • Hazards include natural and human caused events and conditions across varying temporal and spatial scales, accidents, and deliberate acts that damage, reduce functionality and services, and affect social and economic outcomes that lead to illness, injury, or loss of life.
  • Multihazards denotes the occurrence of more than one hazard and the interaction among them as independent, simultaneous, coupled, successive, cascading, or compounding, which threaten a specific community or geographic region.
  • Resilience is the ability to plan, prepare for, mitigate, and adapt to changing conditions from hazards to enable rapid recovery of physical, social, economic, and ecological infrastructure. Improving resiliency before, during, or following a hazard event should engage physical infrastructure and social systems with adaptive capacity to ensure rapid return to functionality, accounting for interdependencies within and across all sectors.

Issue 

In the aftermath of diverse natural and human-made disasters there have been various definitions of critical infrastructure, hazards, multihazards (sometimes referred to as disaster diversity and polyhazards), and resilience. Unified definitions facilitate development of industry and building standards and useful metrics for progress in this vital area. 

Rationale 

As an individual member professional organization representing practitioners in the public and private sectors, as well as educators, ASCE is uniquely qualified to provide definitions which can be used to clarify the discussion in government and the infrastructure industry at large. An all-hazards approach is used in the government and emergency management communities, while the engineering community uses a multihazards approach to address infrastructure resilience. It is important to recognize and define the context for both approaches. These baseline definitions will aid in the development of standards and federal, regional, state, and local legislation and regulation.

ASCE Policy Statement 518
First Approved in 2006