At least five people have died following an unprecedented blackout in Spain and Portugal to a standstill.

A family of three – husband, FDR, 81, his wife, AFM, 77, and their disabled son, JFDF, 56 – are among five people who have died since Spain and Portugal went dark.

The married couple and their son were found dead , April 28, at their home in Taboadela, a town of less than 1,500 in Galicia, northeast Spain.

The father, 81, who required a respirator, his wife, 77, and their disabled son, 56, are believed to have died of carbon monoxide poisoning after a domestic generator or a fuel appliance malfunctioned.

The father was a well-known justice of the peace who suffered from a serious illness that required him to use a respirator. Investigators believe that the generator the family was using to keep his respirator on during the power outage malfunctioned. As they were upstairs in the house, they inhaled carbon monoxide.

The blackout saw thousands of train passengers stranded and left millions of people without phone and internet coverage and access to cash from ATMs across the Iberian Peninsula.

Dozens of flights were also cancelled, with passengers scrambling to know their rights.

Prime Minister Pedro Sánchez said the European grid experienced a “strong oscillation,” but said the cause is still being determined.

He said the Spanish power grid lost 60% of its national demand in just five seconds.

“We have never had a complete collapse of the system,” he added.