The Apsac was a 24th century Malon export vessel, 11th gradient supertanker. The Apsac possessed seven separate shields and was known for being one of the safest Malon tankers in service. (DS9 - Gateways novel: Demons of Air and Darkness)
The Apsac was an upgraded 11th gradient supertanker conceived by Controller Marssi. In addition to he reinforced tanks, the Apsac was equipped with seven separate shields to improve redundancy. These shields were enhanced further by a shield enhancer component.
As a result, the Apsac was especially lucrative, allowing Marssi to pay higher wages to her core laborers. Marssi's profit margin was so huge she had recouped Apsac's construction costs with the second trip, and sufficient to buy a house in the mountains after the third. (DS9 - Gateways novel: Demons of Air and Darkness)
The Apsac was conceived after the most profligate controller, Emck, was killed and his ship destroyed in the Void by USS Voyager at stardate 52081.2 (January 2375). His success had threatened to put other controllers out of business. Following his death, Marssi was able to secure the funding to build the Apsac. (VOY episode: "Night", DS9 - Gateways novel: Demons of Air and Darkness)
Marssi conceived the Apsac and oversaw its construction. The Apsac was built on Malon Prime. Marssi succeeded when other Malon had believed she would fail because of her being a woman and her technical innovations.
By 2376, the Apsac had completed two highly lucrative waste export trips.
In May 2376, the Apsac was attacked and damaged by a Hirogen hunter escort, forcing the crew to dump its hazardous cargo into an Iconian gateway. The antimatter waste passed through the gateway to a location near Europa Nova in the Alpha Quadrant. A Hirogen alpha would later transport aboard the tanker and kill the crew. Kira Nerys and Taran'atar were successful in destroying the Malon tanker, preventing any more waste entering the gateway. (DS9 - Gateways novel: Demons of Air and Darkness)