Stockholm - Four Swedish slaughterhouses face action by authorities for failing to secure proper protection for pigs going to slaughter, reports said Tuesday.

Several cases where pigs were scalded to death were documented by the National Food Administration in 2008, Swedish radio news reported.

Food group HK Scan that operates or has interests in the four slaughterhouses in question conceded the mistakes. Scan slaughtered some 1.9 million pigs in 2008.

Veterinary Christer Lindberg observed two cases where pigs had not been sedated properly before slaughter, and were later seen moving while being processed in a tub filled with boiling water at a slaughterhouse in Lulea, northern Sweden, the radio report said.

The plant's managing director Michael Hugosson said there was "no excuse" for the incidents. "The animals' welfare should never be at stake but there is a risk of it, since we operate on such a tight schedule," Hugosson said.

Probes have been launched over possible violations of legislation ensuring protection of animals.

Agriculture Minister Eskil Erlandsson expressed concern over the reports and urged tighter checks by both slaughterhouses and supervisory authorities. (dpa)