The company said in a Wednesday press release that the leak was about 70 kilometres from Plock, the site of a major refinery in central Poland. PERN said the Druzhba pipeline is the main line transporting crude oil to Germany.
"At this time, the causes of the event are unknown although pumping through the damaged stretch has been ruled out," PERN wrote in a press release. "The other stretch of the pipeline is working unaltered," the company added.
PERN said that remaining elements of the pipeline infrastructure, including a maritime stretch through which crude oil carried to Poland and later to Germany by tankers is pumped, are working normally.
PERN rescue services and the State Fire Service are at the location of the leak to secure the site, PERN said.
Around 400 cubic metres of petrochemicals have been pumped out of the damaged stretch, transit through it has been blocked and the pressure has dropped, a fire service spokesperson said.
Stanislaw Zaryn, director of the National Security Department, said the leak would not threaten Poland's security.
"The scale of the event is not something that would affect the security of Poland, but of course what is happening, what we are dealing with in Europe, indicates that such leaks must be checked very thoroughly and that is why we will do everything to establish the final findings as soon as possible," he said. (PAP)