LOS ANGELES — Citing harm to marine life, California coastal regulators on Wednesday soundly rejected a utility’s plan to map offshore earthquake faults near a nuclear power plant by blasting loud air cannons.
The unanimous vote by the California Coastal Commission came after an hours-long public hearing attended by environmentalists, fishermen and residents who were overwhelmingly opposed to the testing.
The proposed survey by Pacific Gas & Electric Co. involves firing sonic pulses into the ocean. Sensors on the seafloor would pick up the echoes to create 3-D maps of geologic faults that the utility said are needed to understand the seismic hazards around the Diablo Canyon facility.
“If you live near a nuclear plant, wouldn’t you want more certainty in the assumptions that are being made?” said Mark Krausse, a PG&E director.
But commissioners said the impact to sensitive marine mammals along the Central Coast would be too great, and they felt PG&E did not make the case that such testing was necessary.
In a statement, PG&E said it was disappointed with the decision and will evaluate its next move. It could reapply for a permit, but several commissioners indicated they would be hard-pressed to change their minds.
The commission’s staff had urged the panel to reject the plan. In a report this month, the staff said sonic blasts would cause “significant and unavoidable impacts to marine resources.” More than 7,000 sea mammals would be disturbed by the ear-piercing noise.
PG&E acknowledged that the noise could cause short-term disruption to animals, but said similar research has been done around the world without long-term harm.