[15] X-Press Pearl carried 1,486 containers, with contents including 25 tons of nitric acid (which can be used in the manufacture of fertilisers and explosives), other chemicals, cosmetics and low-density polyethylene (LDPE) pellets, when it departed the port of Hazira on 15 May 2021, arriving off Colombo on 19 May.

[16][17] By 11 May the crew had discovered that a container loaded at Jebel Ali was leaking nitric acid, and had requested both Hamad and Hazira ports to allow it to be offloaded, but permission was not granted.

[18] According to X-Press Feeders, the requests were denied as "there were no specialist facilities or expertise immediately available to deal with the leaking acid", and the vessel proceeded on its planned journey to Colombo.

[23] Though initial reports linked the incident to leaking acid, Harbor Master De Silva said the fire had broken out in the number 2 hold of X-Press Pearl while the container was stacked on deck.

[24][25] Two Indian crew members who sustained injuries during the explosion were admitted to the Colombo's National Hospital of Sri Lanka.

The Sri Lanka Maritime Environmental Protection Authority (MEPA) declared a Tier II oil spill event from on-board bunkers as the blaze got worse.

[28] India dispatched firefighting and pollution control Coast Guard vessels, a tug and a Dornier maritime reconnaissance aircraft to help containment measures, and fishermen were asked to stay clear of the ship.

[29][30] Chairperson of MEPA Dharshani Lahandapura said on 26 May that 378 tonnes of oil were on board the vessel and about half could leak into the sea after the fire ended.

Bad weather prevented the deployment of oil-containment booms around the ship, but authorities were ready to clean up any oil that reached the shore.

The Indian Coast Guard vessel ICG Samudra Prahari, a pollution control ship, joined the task force.

[35] On 21 May 2021, Sri Lankan Navy deployed two offshore patrol vessels, naval ships such as Sagara and Sindurala along with an aircraft in firefighting rescue operations which went in full swing despite inclement weather conditions surrounding the area.

[42] On 2 June 2021, X-Press Feeders issued a statement saying the company "regret[s] to report that despite salvors successfully boarding the vessel and attaching a tow wire, efforts to move the ship to deeper waters have failed".

[43] Health experts and MEPA also warned that there are possibilities for mild acid rains in Sri Lanka due to the emission of nitrogen dioxide.

Dead fish and turtles continued to wash up on Sri Lanka's beaches and were examined to determine if their deaths were caused by the spill.

[54] On 2 June, salvors set up a line towing X-Press Pearl away from the coast when the stern hit bottom, forcing them to abort the operation.

[58] Authorities in Sri Lanka continued to collect debris and plastic pellets in what was described as the biggest ever nurdle hunt in the country.

[69][70] Sri Lanka Police questioned the chief officer of X-Press Pearl over two days on the vessel's container stowage plan.

The ship was carrying multiple classes of dangerous goods including sodium hydroxide (caustic soda) in holds as well as at least one container of nitric acid which was leaking on deck.

[73][74] On 31 October, OpenFacto, the French Collective for open source research, published an investigation[75] tracking the nitric acid container to Iran where it was allegedly sold by a broker company called ChemiPakhsh Paykan and produced[76] by Esfahan Chemical Industries, a sanctioned[77] affiliate of the Iranian Ministry of Defence.