Table 1. Summary of Orphaned and Abandoned Oil and Gas Well Definitions.

Well status	Production	Plugging status	Legal responsible operator	Financial responsibility	Examples of other terms used by statesa
Abandoned	Nonproducing or not authorized for production	Plugged or unplugged	Active and able to plug and remediate the well	Operator	Suspended, shut-in, temporarily abandoned, inactive, idle
Orphaned	Nonproducing or not authorized for production	Unplugged	Unknown, unavailable, or insolvent and is unable to plug or remediate the well	State, other government agency, and/or the general public	Abandoned, revoked, forfeited, unknown, shut-in

^aThe terms are based on documented orphaned well data compiled as of January to April 2022. State-specific terms can be found in Table S4.