Media articles reported a 600m long oil slick landed on 27 Jun on the mangroves and intertidal flats of the nearly 500-ha national park. The spill was believed to have occurred during fuel transfer from vessels off Tanjung Piai.
Here's more about Tanjung Piai from the Ramsar website:
Tanjung Piai. Johor
526 ha; 01°16'N 103°31'E. State Park.
The site consists of coastal mangroves and intertidal mudflats located at the southernmost tip of continental Asia, especially important for protection from sea-water intrusion and coastal erosion. Tanjung Piai supports many threatened and vulnerable wetland-dependent species such as Pig-tailed Macaque and Long-tailed Macaque, birds like Mangrove Pitta, Mangrove Blue Flycatcher, Mangrove Whistler. Globally vulnerable Lesser Adjutant may be observed in the vicinity of the site. The Scaly Anteater, Common Porcupine, Smooth Otter and Bearded Pig are classified as vulnerable or near threatened listed in the IUCN Red Book 2000.
Waters of the four main rivers traversing Tanjung Piai are abundant with commercially valuable species. The site enjoys the status of a State Park for eco-tourism -- a visitor centre with boardwalks near the southern tip of the park provides interpretive materials, guided walks, and overnight facilities, with a World Wetlands Day programme beginning in 2003.
Due to increased sea traffic, the western side of Tanjung Piai has been affected by oil spills which caused natural erosion processes in nearly 70 ha of the mangrove forest. In addition, the new port being established in the estuary of Sungai Pulai will likely lead to increased wave energy reaching the east shore of Tanjung Piai, thus accelerating coastal erosion.