Aliso Canyon: prolonged methane storage leak

The allegation

A gas-storage well leaked methane and associated chemicals for nearly four months in 2015–16. Claim: safety oversight and response were inadequate. Emissions are measured; intentional release or proven chronic community illness is not.

Timeline

Leak began Oct. 23, 2015, was publicized later that month, and was plugged in Feb. 2016. Thousands of households relocated; safety reforms followed.

What the record establishes

CARB estimates, aircraft measurements, and peer-reviewed analysis quantify a major methane release. State investigations examined well integrity and oversight.

Counterevidence and alternative explanations

Methane’s climate effect is clear; local health concerns involve co-emitted compounds. Symptom reports are real but nonspecific; relocation reduced exposure.

Uncertainty and limits

Pre-event baseline and individual exposure records are limited. Mixtures and follow-up complicate chronic effect estimates.

Calibrated skeptical verdict

Prolonged uncontrolled leak and serious system failures are established. Specific chronic health causation remains uncertain; intentional release is unsupported.

What could change the assessment

Well-integrity records, independent emissions monitoring, health follow-up, and storage-field audits could refine exposure and responsibility.

Annotated authoritative sources and source limits

1. CARB Aliso Canyon emissionsState estimate based on aircraft and atmospheric observations.
2. Conley et al., Science (2016)Peer-reviewed aircraft measurement of methane emissions.
3. California PUC Aliso CanyonRegulatory investigations and storage-safety proceedings.