Acceptable Entry: Those conditions that should exist in a confined space that allow entry and
ensure that employees can safely work within and exit the space.
Access Control Point: An opening in the physical boundary between work zones which is used
to regulate movement of personnel or equipment between the zones.
Acclimatization: A process that helps an employee adjust to work under extreme conditions
(e.g., temperature, altitude).
Action Level: A contaminant concentration at which additional measures are implemented to
protect the worker. The protective measures may include medical surveillance, training, and
modification of the level of protection.
Activity Hazard Assessment (AHA): The process to identify and evaluate the operational
activities and their associated hazards. The process includes implementing control measures to
eliminate or reduce each hazard to an acceptable level.
Administrative Controls: Provisions related to the organization and management, procedures,
recordkeeping, assessment, and reporting necessary to ensure safe operation of a facility.
Assessment: The evaluation or appraisal of a process, program, or activity to determine
compliance with the relevant standard, DOE order, rule, code, regulation, or other appropriate
Attendant: The individual stationed outside a confined space who monitors the authorized
entrants, controls access into the confined space, and is alert to any hazards that may arise.
Authorized Entrant: An employee who is authorized by the employer to enter a confined space.
Biological Hazards: Agents presenting hazard to the well-being of humans or other animals,
either directly through infection or indirectly through disruption of the environment. Hazards
include plant exposures (e.g., poison ivy and poison oak) and animal exposures (e.g., bee stings
and snake bites).