Israel has dispatched two massive chemical tankers carrying phosphoric acid to Gaza. These vessels are currently en route. The "relevant authorities" are actively searching for these tankers in order to prevent them from entering Gaza. Yemeni Houthis intercepted a third Israeli-owned boat on their coastline yesterday, which was also transporting phosphoric acid. The chemicals are now in Yemen.
Update:
The tanker carrying the chemicals has been seized by unidentified armed individuals in the Gulf of Aden.