Editing Oil spill (section)

=== Oil tankers and vessels ===
Vessels can be the source of oil spills either through operational releases of oil or in the case of [[oil tanker]] accidents. As of 2007, operational discharges from vessels were estimated to account for 21% of oil releases from vessels.<ref name=":3" /> They occur as a consequence of failure to comply with regulations or arbitrary discharges of waste oil and water containing such oil residues.<ref name=":4">{{Cite book|last1=Mu|first1=Lin|title=Information Engineering of Emergency Treatment for Marine Oil Spill Accidents|last2=Wang|first2=Lizhe|last3=Yan|first3=Jining|publisher=CRC Press|year=2019|isbn=9780429289101|location=Taylor & Francis Group|pages=1–30|chapter=Emergency Response System for Marine Oil Spill Accidents}}</ref> Such operational discharges are regulated through the [[MARPOL 73/78|MARPOL convention]].<ref>{{Cite web|title=MARPOL Annex I – Prevention of Pollution by Oil|url=https://www.imo.org/en/OurWork/Environment/Pages/OilPollution-Default.aspx|access-date=2021-05-27|website=International Maritime Organization}}</ref> Operational releases are frequent, but small in the amount of oil spilled per release, and are often not in the focus of attention regarding oil spills.<ref name=":3" /> There has been a steady decrease of operational discharges of oil, with an additional decrease of around 50% since the 1990s.<ref name=":1" />

{{as of|2007|post=,}} accidental oil tank vessel spills accounted for approximately 8–13% of all oil spilled into the oceans.<ref name=":3" /><ref name=":5">{{Cite journal|last1=Galieriková|first1=Andrea|last2=Materna|first2=Matúš|date=2020|title=World Seaborne Trade with Oil: One of Main Cause for Oil Spills?|journal=Transportation Research Procedia|volume=44|pages=297–304|doi=10.1016/j.trpro.2020.02.039|s2cid=216537436|doi-access=free}}</ref> The main causes of oil tank vessel spills were collision (29%), grounding (22%), mishandling (14%) and sinking (12%), among others.<ref name=":3" /><ref>{{Cite journal|last=Yamada|first=Yasuhira|date=October 2009|title=The Cost of Oil Spills from Tankers in Relation to Weight of Spilled Oil|journal=Marine Technology|volume=46|issue=4|pages=219–228|doi=10.5957/mtsn.2009.46.4.219}}</ref> Oil tanker spills are considered a major ecological threat due to the large amount of oil spilled per accident and the fact that major sea traffic routes are close to [[Large marine ecosystem|Large Marine Ecosystems]].<ref name=":3" /> Around 90% of the world's oil transportation is through oil tankers, and the absolute amount of seaborne oil trade is steadily increasing.<ref name=":5" /> However, there has been a reduction of the number of spills from oil tankers and of the amount of oil released per oil tanker spill.<ref name=":5" /><ref name=":1" /> In 1992, [[MARPOL 73/78|MARPOL]] was amended and made it mandatory for large tankers (5,000 dwt and more) to be fitted with [[double hull]]s.<ref>{{Cite web|title=Construction Requirements for Oil Tankers – Double Hulls|url=https://www.imo.org/en/OurWork/Environment/Pages/constructionrequirements.aspx|access-date=2021-05-27|website=International Maritime Organization}}</ref> This is considered to be a major reason for the reduction of oil tanker spills, alongside other innovations such as [[Global Positioning System|GPS]], sectioning of vessels and [[sea lane]]s in narrow straits.<ref name=":1" /><ref name=":3" />

In 2023, the International Tanker Owners Pollution Federation (ITOPF) documented a significant oil spill incident of over 700 tonnes and nine medium spills ranging between 7 and 700 tonnes. The major spill occurred in Asia involving heavy fuel oil, and the medium spills were scattered across Asia, Africa, Europe, and America, involving various oil types.<ref name=":10">{{Cite web |title=Oil Tanker Spill Statistics 2023 – ITOPF |url=https://www.itopf.org/knowledge-resources/data-statistics/statistics/ |access-date=2024-04-12 |website=itopf.org}}</ref>

The total volume of oil released from these spills in 2023 was approximately 2,000 tonnes. This contributes to a trend of decreased oil spill volumes and frequencies over the decades. Comparatively, the 1970s averaged 79 significant spills per year, which drastically reduced to an average of about 6.3 per year in the 2010s, and has maintained a similar level in the current decade.<ref name=":10" />

The reduction in oil spill volume has also been substantial over the years. For instance, the 1990s recorded 1,134,000 tonnes lost, mainly from 10 major spills. This figure decreased to 196,000 tonnes in the 2000s and 164,000 tonnes in the 2010s. In the early 2020s, approximately 28,000 tonnes have been lost, predominantly from major incidents.<ref name=":10" />