Natural gas

Restoring gas after an earthquake means assessing the system in the affected area, repairing the damage, reactivating the system, then visiting each home to relight all affected appliances. [2]

Water and electricity come back when the network is repaired. Gas comes back when a qualified person has been inside the building and relit every gas appliance in it, one building at a time.

If the pressure in the pipes falls away before the meters can be shut, air is drawn into the system and has to be taken out again before anybody lights anything.

A controlled shutdown is one the utility gets notice of. The same order treats 72 hours of notice as enough time to carry one out, and records uncertainty about whether a controlled shutdown is possible at all with less. [3] An earthquake gives no notice.

FortisBC’s 2024 forecast, filed with its regulator in March 2026, counts 583,370 residential gas accounts and 61,348 commercial ones in its Lower Mainland service region. [4] An account is a meter: a house is usually one account, and an apartment building on a central gas boiler is one account serving everybody in it.

Against that, the rate:

8,716 is the highest of the rates the plan publishes. It counts FortisBC’s whole workforce, mutual aid crews sent by other utilities and every available private gas contractor in the Lower Mainland. Without those outside crews, FortisBC’s own figures are 2,025 a day and 723 a day. [1] The plan also assumes a quarter of customers relight their own appliances. [1]

Whether outside crews arrive depends on the earthquake, not on the gas system. Those crews reach buildings the way everybody else does, over the same roads and on the same fuel. FortisBC has published no relight rate for a megathrust, and none can be worked out from these figures.

In October 2025 the BC Utilities Commission approved an LNG storage expansion at Tilbury in Delta, reasoning from a different hazard: a prolonged loss of supply on the T-South pipeline in winter. The panel wrote that such an outage, with no earthquake damage anywhere in it, “would put hundreds of thousands of customers at risk of losing service”, and that FEI’s evidence showed “a loss of service at this scale would take several weeks to restore service”. [3] FortisBC’s own modelling of comparable supply interruptions, again with no earthquake damage in them, pairs customer counts of roughly 600,000 to 640,000 with total outage durations of 57 to 70 days. [1]

There are no broken mains in that scenario, no air in the pipes, no buildings a technician cannot safely enter and nobody else competing for the same contractors, and the relight rate underneath it is the 8,716 one. Every one of those conditions gets worse in an earthquake and none gets better, so those durations are a floor.

Two of the outside parties in the proceeding told the commission FortisBC was being too cautious: one submitted “that FEI’s restoration and relight plan is overly conservative”, and another argued that relighting business and industrial customers earlier “could dramatically reduce the GDP losses incurred”. The panel found FEI’s assumptions “reasonable and appropriate”. [3]

The LNG storage tank at the Tilbury base plant was installed in 1969. Seismic design requirements have tightened since, and to comply with them FortisBC runs the tank at 58 per cent of its capacity: 0.35 billion cubic feet, down from 0.6. [3]

Two engineering firms examined whether the tank could be refurbished to its full design capacity while meeting current minimum seismic requirements. Both recommended replacing it instead. CB&I called remediation “fraught with significant risk”. WSP concluded that even if every repair CB&I identified could be completed, it would not be cost-effective or feasible to replace the foundation to avoid the tank “failing due to earthquake-caused differential settlement”. [3]

In October 2025 the commission’s panel agreed that refurbishment “does not appear to be a cost-effective or viable option due to seismic issues and the age and condition of the assets”, and approved a replacement at about $1.14 billion in as-spent dollars over a seven-year construction period. [3]

The 2024 plan’s Lower Mainland initiative is to isolate the region’s distribution system after a seismic event that damages assets across it. The scope is additional valves and upgrades to existing ones, all of them able to “autonomously shut following a seismic event”, and the plan says that “Development for this initiative is in the preliminary stages”. [1] The public version carries no budget, no commitment and no date for it.