This file contains the redacted survey questionnaire developed and administered as part of research investigating process safety risks and their environmental, health and safety implications in biogas management at sewage-treatment facilities.

The survey was designed to capture participants’ experience and perceptions of process safety and biogas system risks, including gas leaks, equipment failure, fires and explosions, toxic gas exposure, general site risks, causes and frequency of biogas system failures, and the relationship between system failure and safety incidents.

The questionnaire also examines human and organisational factors affecting process safety, including training, safety culture, communication, reporting of safety concerns and near misses, human error, organisational resources, supervision, and employee confidence in identifying and addressing hazards.

A further section focuses on Process Safety Management Systems (PSMS) and risk mitigation, covering the perceived effectiveness of safety measures, inspection frequency, maintenance, emergency response, employee training, safety equipment, risk assessment and hazard identification, incident investigation, and areas requiring further improvement.

The final section contains open-ended questions allowing participants to provide recommendations for improving process safety, PSMS effectiveness, organisational culture, preparedness, training, and resources.

The document also includes the participant information and formal consent sections used during data collection. Organisationally sensitive information has been redacted where appropriate. This file represents the survey instrument and does not contain identifiable participant responses.