The announcement by Siemens Energy that many of its wind turbines could suffer from faulty components could be the tip of the iceberg, CNBC reported Monday.

This does not sound good.

The company announced on June 22 that between 15% and 30% of turbines installed by subsidiary Siemens Gamesa are currently suffering from component failure, prompting the company to withdraw profit estimates and sending stock plunging 36% in the immediate aftermath of the announcement. Christian Burch, CEO of Siemens Energy, said in a call with reporters Friday that “too much had been swept under the carpet” at the energy giant’s subsidiary and that the quality control issues were “more severe than [he] thought possible,”