NEW ULM — A judge’s ruling saying an air compressor service company wasn’t financially responsible for a fire that nearly destroyed a New Ulm butter plant in 2004 has been upheld by the Minnesota Court of Appeals.

Associated Milk Producers Inc. challenged the ruling, which was made by former Brown County District Court Judge John Rodenberg in December. The ruling said Compressor Services, a business that was providing maintenance for one of two compressor systems in the area where the fire started, couldn’t be legally linked to the fire.

The AMPI manufacturing plant in downtown New Ulm caught fire Dec. 1, 2004. Several fire departments spent more than 12 hours putting out the blaze, which spread quickly through the plant. It took days to clean up the melted butter that had flowed into the streets and downhill toward the Minnesota River.

An investigation, which was described in the appeals court ruling, later determined a Sullair compressor had been having maintenance problems for several months. It had been shut off before the fire started because it was leaking lubricating oil. The leak was discovered late in the afternoon, so the maintenance staff shut the compressor down for about 20 minutes to add 2 to 3 gallons of oil. They planned to call Compressor Services the next day.

While that compressor was off, a less powerful Atlas Copco air compressor was providing the air compression needed for the factory’s machinery. The Sullair compressor was turned back on at about 5:15 p.m. About an hour later there was an explosion in the compressor mezzanine and flames shot out of the Atlas Copco compressor.

Experts examining the fire damage found the Atlas Copco compressor hadn’t been grounded properly and didn’t have pressure or temperature sensors. They also found that the fire spread quickly through the mezzanine’s walls and ceiling tiles, which were made of flammable materials. Cardboard boxes also were stored in the area, helping feed the fire.

Atlas Copco and Sullair were included in AMPI’s original lawsuit, but AMPI settled with those companies before the appeal was filed.

The claim against Compressor Services was that the business hadn’t properly maintained the Sullair compressor and hadn’t made AMPI maintenance staff aware of leakage problems. When the compressor had been repaired by Compressor Services earlier that year, a technician used silicon seals to repair a persistent oil leak. Sullair had put out bulletins to Compressor Services, which hadn’t been passed on to AMPI maintenance staff, that recommended using a different type of seal.

If the Sullair compressor hadn’t broken down, the Atlas Copco compressor wouldn’t have had to work harder to provide compressed air that night, the AMPI lawsuit said. It also claimed the oil that had leaked helped the fire spread so quickly.

Rodenberg’s ruling said the fact that Compressor Services hadn’t warned AMPI about Sullair’s warnings was irrelevant because even AMPI’s experts determined the fire started in the other compressor. Rodenberg noted that one AMPI expert said the insulating foam around the Atlas Copco compressor was “the ladder fuel” that caused the fire to spread to the walls, ceilings and boxes around the compressors. Other AMPI experts said the oil did help the fire spread, but they were compressor experts not experts in how fires spread.

Citing expert testimony that said the oil wouldn’t have burned hot enough or fast enough to cause the rapid spread of the fire, Rodenberg also said the pooling oil from the Sullair compressor didn’t contribute to the massive damage to the factory.

A three-judge panel from the Court of Appeals agreed with Rodenberg’s assessment. The appeals ruling also said AMPI would have to pay Compressor Services legal costs.

Rodenberg was appointed to the Minnesota Court of Appeals earlier this year. He was not on the panel that reviewed this case.