India’s southern state of Kerala was on high alert Sunday after a Liberian-flagged vessel carrying hazardous cargo sank off its coast, reports Arab News.

The Indian Ministry of Defense said the 184-meter MSC Elsa 3 container ship was en route to Kochi from Vizhinjam on Saturday when it issued a distress call.

All 24 members of the vessel’s crew — which included nationals of Russia, Ukraine, Georgia, and the Philippines — were rescued by the Coast Guard and the Navy.

“The vessel went down with 640 containers, including 13 with hazardous cargo and 12 containing calcium carbide,” the ministry said.

It did not specify what other hazardous substances were onboard, but calcium carbide becomes dangerous on contact with water, producing acetylene gas, which is flammable and explosive.

The vessel was also loaded with more than 84 metric tons of diesel and 367 metric tons of furnace oil.

Diesel and furnace oil are both classified as marine pollutants. They are toxic to marine life and can contaminate coastal ecosystems.

The Kerala State Disaster Management Authority issued a public warning on Saturday, when the ship started losing containers in the Arabian Sea. The authority’s secretary told reporters that “there is a chance the cargo, including containers and oil, will wash ashore.”

The Indian Coast Guard has deployed spill detection systems.

“ICG aircraft equipped with advanced oil spill mapping technology are conducting aerial assessment of the affected area,” it said. “As of now, no oil spill has been reported.”

What complicates pollution response is strong currents off the coast of Kerala, which, if leakage occurs, may move the spill toward the south, to Alleppey and Kollam districts, Prof. Biju Kumar, dean of the Faculty of Science, University of Kerala, told Arab News.

“These are the best fishing grounds, as far as Kerala is concerned. Any kind of oil spill will have consequences that will affect marine life. The major issue will be the fish fauna,” he said.

“The major threat is polycyclic aromatic hydrocarbons, which are the most toxic component in any oil. They may be absorbed by plankton, which is a major food source for the commercially available fish … The PAH will remain in the water for a longer time. It essentially means that we need long-term monitoring if it happens.”