More than 18,000 cows died after an explosion and subsequent fire on a family dairy farm in west Texas. It is the deadliest farm fire of its kind on record in the United States.

Although the exact number of cows killed by the fire and smoke that followed the explosion remains unknown, the sheriff’s office told the BBC it was “estimated that 18,000 cows were lost”.

In addition to the cows from the explosion, at South Fork Dairy near the town of Dimmit, one person was injured and is in critical condition.

Speaking to local news agency KFDA, Sheriff Sal Rivera said most of the cattle were lost after the fire spread to an area where the cows were kept before being taken to the milking area and then to a pen.

“There are some cows that survived. There are some who are probably injured to the point where they should be euthanized.” he said.

The cause of the fire is under investigation, however, authorities believe the explosion may have been fueled by methane.

According to the AWI, nearly 6.5 million farm animals have died in farm fires since 2013, including about 6 million hens and about 7,300 cows.