Fairfield firefighters battled a fire late last night they say was set in an abandoned warehouse off lower Black Rock Turnpike.

The fire, set deep within a 50,000-square-foot structure at 81 Black Rock Turnpike, was discovered at approximately 10:05 p.m. when a Fairfield police officer on patrol spotted smoke rising from the site.

The challenge for firefighters proved to be getting access to the fire, located in a pit near the back of a warehouse behind Planet Fitness. Assistant Fire Chief Stephen Curry said that distance, combined with the nighttime darkness, heavy smoke and unsafe conditions all worked to create a scenario that required extra equipment and precaution.

Hoses from three engine trucks were connected and stretched through the warehouse to the site of the blaze. Once there, the flames in a pile of rubbish were quickly extinguished.

Based on the immediate evidence, including the fact there are no active utility connections in the structure, Curry said the fire "would have to have been set."

The fire marshal's office is investigating the blaze, and is working with the property owner to upgrade security to prevent any further incidents.

According to the town's tax records, the 4.9-acre property is owned by Edward S. Reiner, trustee, and is appraised at $7,179,300.

In addition to the three engine trucks, firefighters dispatched two ladder trucks and Rescue 1 to the scene. The last unit cleared the scene about 10:45 p.m.