The July 2 blaze, caught on video apparently from a nearby helicopter, showed bright orange flames jumping out of the water as the fire raged a short distance from the oil platform. Pemex has previously said it took more than five hours to fully extinguish the fire.
"There was no oil spill and the immediate action taken to control the surface fire avoided environmental damage," the company said in a statement on Monday.
The statement added that the blaze was sparked by an electric storm that ignited a leak of gas from a busted underwater pipeline.
The fire ignited a storm of criticism over the weekend, including social media posts from climate activist Greta Thunberg and New York Mayor Bill de Blasio, among many others.
The fire took place at the top producing offshore oilfield operated by Pemex, which has a long track record of major industrial accidents at its facilities.
The state-run company reiterated that it will investigate the cause of the pipeline gas leak further.