NASA Earth Observatory image modified by SkyTruth
In the early hours of February 28, the MT Princess Empress — an oil tanker following a common shipping route in the Philippines — encountered rough seas and strong winds while en route from Limay, Bataan to Iloilo City. The ship started to take on water and suffered engine trouble as the waves tossed it around in the waters off Oriental Mindoro. After putting out a distress call, the captain and 19 crewmembers were rescued from the sinking tanker by a nearby cargo ship. The unmanned Princess Empress continued to drift toward Balingawan Point in Naujan, where it finally submerged about 14 km (9 mi) from shore.
Data credit: AIS signals acquired from Spire Global via Global Fishing Watch, and ShipView.
The Princess Empress, owned by the Filipino company RDC Reield Marine Services, was a 1,143 ton vessel. On the day that it sank, the tanker was transporting around 800,000 liters (211,000 gallons) of industrial fuel oil, which started to escape shortly after the tanker submerged. The Philippine Coast Guard documented a 5 kilometer (3.1 mi) long, 500 meter (1600 ft) wide oil spill later that day. Yet for several critical days there was apparent confusion over the exact location of the sunken tanker, in part because of its failure to broadcast an automatic identification system (AIS) signal as required by international law.
Given clear enough weather conditions and sufficient satellite coverage, satellite images can reveal oil slicks and help to estimate the volume of oil floating on the surface of the water. As early as March 3, oil could be seen around the Princess Empress shipwreck site in satellite imagery. Despite national and international efforts to contain the spill, oil continued to leak into the sea for months. In March, the Philippines Department of Environment and Natural Resources (DENR) estimated that 35,000-50,000 liters (9,250-13,200 gal) of oil were escaping the sunken vessel per day. As of June 17, the remediation team finished extracting oil from the sunken tanker; however, some oil could still be seen streaming from the submerged ship in satellite images from June 24.
Oil reported in area
Oil spill footprint
Data credit: Affected areas from Philippine National Disaster Risk Reduction and Management Council report.
Missed signals
At around 6:21 p.m. Philippine time on February 26, the Princess Empress left the port in Limay and began its voyage toward Iloilo City. The ship started off the journey signaling its location every 2 to 22 minutes; however, it abruptly stopped sending AIS signals after 9:31 p.m., and two days later, it sank about 173 kilometers (107.5 mi) away. This was not the first instance in which the Princess Empress sailed without sending AIS signals; there were multiple gaps in the signal broadcast while the ship sailed to the port at Limay.
Data credit: AIS signals acquired from Spire Global via Global Fishing Watch, and ShipView.
The International Convention for the Safety of Life at Sea (SOLAS) requires all ships of 300 gross tons on international voyages to be fitted with an AIS system and to continuously broadcast AIS at all times except for safety or security risks, such as transiting waters known to harbor pirates.
However, the provision allowing vessels to stop broadcasting when safety concerns arise has been abused by some vessels that have intentionally disabled their AIS transponders or modified transponder data to mask their movements. This often happens when vessels are trying to hide illicit activity or avoid sanctions. Repercussions for disabling AIS signaling are at the discretion of multiple agencies and therefore often inconsequential. Currently only the United States, Panama, Hong Kong, Indonesia, and Singapore have instituted sanctions or fines related to gaps in AIS broadcasting. With such little oversight, vessels can “go dark” with virtually no concern for financial ramifications.
Disabling AIS signaling can endanger the safety of the captain and crew and increase the risk of disastrous maritime collisions. In the case of the Princess Empress, the lack of AIS signaling when it sank created safety risks and could have hindered the ability of the Philippine Coast Guard to find the shipwreck. Because the crew had sent out a distress call on February 28, the Coast Guard was aware of the ship’s location. But with consistent AIS signaling, the exact location of a distressed ship can be tracked up until it loses electrical power – allowing for expedited oil extraction and remediation efforts.
Oil in water
Industrial fuel oil is dense and viscous, described as “black and thick with a strong odor.” When spilled in water, heavy fuel oils create dark slicks that can be carried by wind and current for hundreds of miles. Often this type of oil will clump, forming tar balls that scatter and wash ashore in various areas around the spill.
Oil spills, like the one caused by the sinking of the MT Princess Empress, can have devastating impacts on coastal communities and surrounding ecosystems. Cleanup requires immense financial resources, labor, and time, and despite best efforts often can’t correct irreversible damage done to local flora and fauna.
According to the latest report issued by the Philippine National Disaster Risk Reduction and Management Council (NDRRMC), more than 200,000 Filipino citizens have been affected by the oil spill, located in 3 regions, 4 provinces, and 20 municipalities.
Data credit: Affected areas from Philippine National Disaster Risk Reduction and Management Council report.
The Princess Empress oil spill has left many people in the affected communities sick, complaining of nausea and dizziness. It has forced the suspension of classes in some schools due to the fumes coming from oil-laden shorelines. Economically, the impact on the livelihoods of thousands of Filipinos working in the fishing and farming industries has been severe with fishing bans in effect for months in some areas. The damage to fisheries alone reached 3.8 billion Philippine pesos ($68.3 million). The Philippine government had to support tourism workers to find alternative livelihood while the spill was ongoing. Additionally, many affected coastal areas were forced to declare a state of calamity, which requires remedial measures to be enacted immediately.
The toll on marine and coastal ecosystems from the Princess Empress oil spill has been significant and will develop into the future. Philippine waters are home to diverse and important ecosystems, from coral reefs to dense mangrove forests. In a biodiversity assessment conducted by the Philippine Department of the Environment and Natural Resources (DENR) on March 6 – 10, the organization found that the affected habitat included 2,251 hectares (22.51km2; 8.7mi2) of coral, 1,286 hectares (12.86km2; 5mi2) of seagrass and 1,647 hectares (16.47km2; 6.4mi2) of mangrove forest. Of the affected locations, 26 were home to nesting sea turtles.
The entirety of the Philippines falls within the Coral Triangle, an important reef ecosystem with the highest coral diversity in the world. One particularly biodiverse and ecologically significant area of the Philippine waters is the Verde Island Passage (VIP), which has been termed the “center of the center of marine shore-fish diversity.” VIP ecosystems support many marine species including aquatic mammals, sea birds, sea turtles, reef fish, corals and invertebrates. The passage contains numerous mangrove forest habitats – a habitat type which is generally recognized as one of the most biodiverse in the world but has suffered alarming decreases worldwide from human activities. Mangroves provide many biological and economic benefits – they protect and stabilize shorelines, feed and house wildlife, improve water quality and act as a carbon sink in the fight against climate change. Oil can have dire repercussions on mangroves with the impacts lasting for a few weeks to several months. Severe spills can lead to permanent habitat loss, decreasing local biodiversity and leaving beaches susceptible to damage from tropical storms and erosion.
Data credit: Habitat distribution from National Mapping and Resource Information Authority (NAMRIA) of Philippines government available through the geoportal PH.
The biggest hazards to local fauna from oil spills like the Princess Empress spill are smothering and ingestion. Sediment on the shoreline can be contaminated for long periods of time, affecting shore birds who feed in intercoastal areas. Fish, dolphins and whales can inhale oil in the water which can damage their lungs and impact their immune systems. Filter feeders like shellfish and corals can be inundated with oil as it mixes in the water column. Even if the oil does not result in the death of the animal, it can make fish and shellfish unsafe for humans and other animals to eat. It is imperative that shoreline cleanup happens quickly to avoid some of the long-lasting impacts from oil spills.
An ongoing problem
In March, the Philippine government declared the spill to be Tier 3 – the highest level of concern, which requires a national and international response. The Philippine Coast Guard was quick to respond, installing spill booms, spraying oil dispersants, supporting local government efforts, and recruiting volunteers to help protect beaches from the approaching oil and to clean up the shoreline after its arrival. Internationally, coast guards from France, Japan, Korea, and the United States provided technical guidance and equipment, and dispatched officers to assist the Philippines with the spill cleanup. An NDRRMC report estimated the volume of oily-water mixture and tar collected from the affected areas was more than 69,900 liters (18,400 gal). Additionally, more than 1,000 drums, 11,000 sacks, 900 tonner bags, and 100 pails of oil-contaminated debris was collected from the 3 affected regions.
To date, the Philippine government has paid 713 million Philippine pesos ($13 million) in assistance to citizens in response to the Princess Empress oil spill. The full cost of the cleanup effort has yet to be calculated, but is expected to reach beyond what the insurance policy of the ship’s owners will cover. The insurance policy payout is also in question, after it was discovered that RDC Reield Marine Services did not obtain an updated permit when it added the Princess Empress to its fleet.
Though the remaining oil in the Princess Empress had been siphoned out by June 17, oil slicks on the surface could still be seen in satellite images weeks later. The cleanup and containment processes are ongoing in the Philippines and the environmental and socioeconomic impacts of the spill will continue to play out into the future.
Major oil spills are not uncommon in the Philippines. There is a high degree of vessel traffic that runs right through the Philippine islands, and through the environmentally-sensitive Verde Island Passage. Many of those vessels carry millions of gallons of fuel oil; and with variable weather through the region, they risk a similar fate to the Princess Empress. In addition to the larger spills, smaller oil slicks appear regularly, often from intentional discharges by vessels in transit. Cerulean – SkyTruth’s tool for detecting oil pollution in the ocean – has found over 120 vessel-caused slicks in Philippine waters since it began analyzing satellite imagery in August 2020. All of these slicks have been reviewed and verified by SkyTruth experts. In addition to oil, a boom in liquefied natural gas (LNG) in the Philippines poses another threat to the health of the environment and coastal communities. LNG has been found to be as bad for the environment as coal due to significant methane leaks and harmful air pollutants. With greater investment in natural gas in the Philippines, the potential for greater levels of pollution coming from both oil and natural gas looms large.
Since the Princess Empress sank, citizen-led initiatives like Bantay Oil Spill and Protect VIP have sought accountability and action in response to this environmental disaster. Grassroots groups are advocating for the Philippine government to take steps toward preventing future spills and to stop the expansion of LNG infrastructure in the ecologically rich Verde Island Passage. To date, no new legislation has been passed to protect the area from disastrous oil spills in the future, or to limit LNG development in the region.
SkyTruth hopes to support these and other initiatives with Cerulean – which uses satellite imagery and machine learning to continuously monitor the earth’s oceans for oil spills. SkyTruth has already shown that South East Asia is a hotspot for illegal dumping of oil and wastewater, and with Cerulean near real-time observation will allow for more identification of pollution events and potential offenders. Cerulean will help to shine a light on the previously obscured chronic issue of oil pollution in the ocean.
