BERLIN - German authorities ordered hundreds of pigs at a farm slaughtered Tuesday after tests showed high levels of a cancer-causing chemical for the first time in swine, as the nation's dioxin scandal widened beyond poultry and eggs.

The top agriculture official in Lower Saxony state in northern Germany called for the animals killed after tests showed illegally elevated levels of dioxin in swine at a farm in Verden known to have purchased tainted feed from the company believed to be responsible for the scandal.

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German firm Harles & Jentzsch GmbH, which produced fat used in tainted feed pellets, is being investigated on allegations it did not alert authorities to the tainted product for months. Samples of the fat contained more than 70 times the approved amount of dioxin, according to tests by the Schleswig-Holstein state agriculture ministry.

"We were specifically investigating this farm, because they had bought their livestock feed from Harles & Jentzsch, the company that delivered tainted feed to all the other farms that had to be banned," Lower Saxony's Agriculture Minister Gert Hahne said.

Hahne did not know yet how high exactly the dioxin levels in the pigs were, but said they were above the allowed maximum levels.

The scandal broke last week when German investigators found excessive levels of dioxin in eggs and then some chicken meat. Authorities then froze sales of poultry, eggs, and, as a precaution, pork, from thousands of farms. Some 558 farms remained closed on Tuesday, said Holger Eichele, a spokesman for the federal agricultural ministry in Berlin.

Agriculture Minister Ilse Aigner said Monday that, while the tainted products posed no direct health risk to humans, officials were working nonstop to find out who and what had contaminated the feed sent to thousands of farms and vowed tough legal action against those responsible.

She said companies should be banned from producing both industrial fats and fats used for livestock, to avoid the possibility that industrial fats could end up in animal feed. Harles & Jentzsch chief Siegfried Sievert has said the company believed that byproducts from palm, soy and rapeseed oil used to make organic diesel fuels were safe for use in livestock feed.

Aigner said her ministry was in talks with the European Union on better controls and monitoring and she was confident they could "find a common European solution."

In Denmark, the Danish Veterinary and Food Administration said Tuesday it was closely monitoring the German scandal and that the tainted feed had also been bought by a Danish company and given to its hens.

The government agency said it and a university concluded that "right now there are no health problems for consumers" if they eat the eggs. It is now also investigating where the eggs may have been used, it said. The hens were bred for laying eggs and not for slaughter.

The EU's food safety system warned Danes on Sunday about the tainted German feed entering Denmark.