The Spanish Geological and Mining Institute (IGME) gave its approval in 2007 to technical studies presented to the Industry Ministry by the company that was interested in building the Castor Project, Spain's biggest underground gas-storage plant.
The confidential proposals presented by Escal UGS, to which EL PAÍS has had access, were considered by the Institute to be "appropriate," according to the report, which is dated January 23, 2007.
But work on the Castor plant, which is located off the coast of the eastern Spanish province of Castellón, had to be halted by the government last week after hundreds of earth tremors were detected in coastal towns.
Back in 2007, the IGME decided that the chances that the Amposta fault, upon which the plant has been built, would reopen were "very small." The document was produced after Escal UGS requested a license to create the Castor plant, which works by storing liquid gas in a depleted oil field located 1,800 meters below sea level.
Basing its decision on the studies presented by the company, the IGME gave its approval to the project. But it does not at any point make specific mention of the risk of seismic activity.
The Ebro Observatory, however, did warn about tremors. The research institute wrote a report during the evaluation of the environmental impact of the project saying that while the plant was "attractive," the "use of the technology in populated areas is susceptible to affecting the danger and the seismic risks of a certain area."