Calcium hypochlorite is used as sanitiser in outdoor swimming pools or as a drinking water disinfectant, says Wikipedia, adding that it is "best kept in a cool dry place away from any organic material. It is known to undergo self heating and rapid decomposition accompanied by the release of toxic chlorine gas".
Maersk has advised Chinese and Hong Kong shippers that containers loaded with the chemical would be refused shipment, in a decision that it said was a precautionary move to "ensure a safe voyage for our vessels", but noted that already loaded consignments would be delivered.
The fire-stricken vessel berthed in Tanjung Palepas to discharge cargo. The ship and its cargo are subject to General Average declaration, a principle in maritime law allowing cargo to be jettisoned or destroyed and expenses incurred in an emergency and the loss shared by all parties with a financial interest in the voyage.