No national tunnel specific fatality count appeared in the sources I could fetch, so this post uses the regulation instead. OSHA's underground construction standard, 29 CFR 1926.800, sets concrete limits that any automated or remote tunneling system must respect.
What the standard requires
- A competent person performs all required air monitoring. Air must contain at least 19.5 percent and no more than 22 percent oxygen.
- At 5 percent or more of the lower explosive limit for methane or other flammable gases, ventilation must be increased or the gas controlled. At 20 percent, workers must be withdrawn above ground and non essential electrical power cut off in the affected area.
- Air quality test records are kept above ground at the worksite.
- Where voice cannot carry, a power assisted voice link is required. Communication systems are tested at the start of each shift, and a lone worker out of range must have a way to get emergency help.
- NIOSH approved self-rescuers must be immediately available, at least one designated person must be on duty above ground whenever anyone is underground, and a check-in and check-out procedure must give an accurate count of people underground.
- Fresh air of at least 200 cubic feet per minute per underground employee, with reversible airflow.
What the software must get right
- Gas thresholds must trigger actions that no AI model can override. The 20 percent withdrawal rule is a hard interlock, not a suggestion.
- Safe stop. If monitoring or communication fails, a tunnel boring or hauling system stops.
- Human approval to restart after ventilation is reduced, in line with the standard's requirement for a competent person to test first.
- Tamper evident logs. Gas readings, communication tests and headcounts are records the standard requires. Software should keep them protected and available above ground.
- Secure updates and offline operation. Signed updates, a known software inventory, and operation with no surface internet link.
Safeguard does not operate tunneling equipment and does not claim to reduce injuries. For makers it offers SBOMs, vulnerability scanning with known exploited status, policy gates, audit logs and air gapped deployment.
Quick check
At what gas level must workers be withdrawn?
At 20 percent of the lower explosive limit, workers are withdrawn above ground and non essential power is cut off.
