• Background
• Major Oil Spills
• Numbers of Incidents and Quantities Spilt
• Seaborne Oil Trade
• Causes of Spills

*** Now updated for 2012 ***

Background

ITOPF maintains a database of oil spills from tankers, combined carriers and barges. This contains information on ACCIDENTAL spillages since 1970, except those resulting from acts of war.

The data held includes the type of oil spilt, the spill amount, the cause and location of the incident and the vessel involved. For historical reasons, spills are generally categorised by size:<7 tonnes, 7-700 tonnes and >700 tonnes (<50 bbls, 50-5,000 bbls, >5,000 bbls), although the actual amount spilt is also recorded. Information is now held on nearly 10,000 incidents, the vast majority of which (81%) fall into the smallest category i.e. <7 tonnes.

Information is gathered from both published sources, such as the shipping press and other specialist publications, as well as from vessel owners and their insurers. Unsurprisingly, information from published sources generally relates to large spills, often resulting from collisions, groundings, structural damage, fires or explosions, whereas the majority of individual reports relate to small operational spillages. Reliable reporting of this latter category of spill is clearly difficult to achieve.

It should be noted that the figures for the amount of oil spilt in an incident include all oil lost to the environment, including that which burnt or remained in a sunken vessel. There is considerable annual variation in both the incidence of oil spills and the amounts of oil lost. Whilst we strive to maintain precise records for all spill information, we cannot guarantee the information taken from shipping press and other sources is complete or accurate; from time to time data may be received after publication, in which case, adjustment to previous entries is made. Consequently, the figures in the following tables, and any averages derived from them should be viewed with an element of caution.

A formatted copy of the following information - ITOPF's Oil Tanker Spill Statistics (6MB) - in Adobe Acrobatis available. Hard copies are also available free of charge, please contact Terry Goodchild (terrygoodchild@itopf.com) to request a copy.

If you would like to receive PowerPoint slides of any of the graphs used on the following pages, please contact Deborah Ansell (deborahansell@itopf.com). For general enquiries about ITOPF's tanker spill statistics, please contact Susannah Musk (susannahmusk@itopf.com).

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Major Oil Spills

A brief summary of the top 20 major oil spills that have occurred since the TORREY CANYON in 1967 is given in Table 1 and the locations are shown in Figure 1; of the 19 largest spills recorded between 1970 and 2002, 95% occurred in the 1970s, 1980s and 1990s, and only 5% occurred in the 2000s. A number of these incidents, despite their large size, caused little or no environmental damage as the oil was spilt some distance offshore and did not impact coastlines. It is for this reason that some of the names listed may be unfamiliar. EXXON VALDEZ and HEBEI SPIRIT are included for comparison although these incidents falls some way outside the group.

Position	Shipname	Year	Location	Spill Size (tonnes)
1	ATLANTIC EMPRESS	1979	Off Tobago, West Indies	287,000
2	ABT SUMMER	1991	700 nautical miles off Angola	260,000
3	CASTILLO DE BELLVER	1983	Off Saldanha Bay, South Africa	252,000
4	AMOCO CADIZ	1978	Off Brittany, France	223,000
5	HAVEN	1991	Genoa, Italy	144,000
6	ODYSSEY	1988	700 nautical miles off Nova Scotia, Canada	132,000
7	TORREY CANYON	1967	Scilly Isles, UK	119,000
8	SEA STAR	1972	Gulf of Oman	115,000
9	IRENES SERENADE	1980	Navarino Bay, Greece	100,000
10	URQUIOLA	1976	La Coruna, Spain	100,000
11	HAWAIIAN PATRIOT	1977	300 nautical miles off Honolulu	95,000
12	INDEPENDENTA	1979	Bosphorus, Turkey	95,000
13	JAKOB MAERSK	1975	Oporto, Portugal	88,000
14	BRAER	1993	Shetland Islands, UK	85,000
15	KHARK V	1989	120 nautical miles off Atlantic coast of Morocco	80,000
16	AEGEAN SEA	1992	La Coruna, Spain	74,000
17	SEA EMPRESS	1996	Milford Haven, UK	72,000
18	NOVA	1985	Off Kharg Island, Gulf of Iran	70,000
19	KATINA P	1992	Off Maputo, Mozambique	66,700
20	PRESTIGE	2002	Off Galicia, Spain	63,000
35	EXXON VALDEZ	1989	Prince William Sound, Alaska, USA	37,000
131	HEBEI SPIRIT	2007	Taean, Republic of Korea	11,000

Table 1: Major oil spills since 1967

 

Figure 1: Location of major spills (click map to view larger version in PDF format (151Kb))

 

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Number of Incidents and Quantity Spilt

 

Figure 2: Large spills (>700 tonnes) as a percentage of those recorded from 1970 to 2009 per decade

 

Number of Oil Spills

The incidence of large spills is relatively low and detailed statistical analysis is rarely possible, consequently emphasis is placed on identifying trends. Thus, it is apparent from Table 2 that the number of large spills (>700 tonnes) has decreased significantly during the last 43 years during which records have been kept. The average number of major spills for the previous decade (2000-2009) is just over three, approximately one eighth of the average for years in the 1970s. Looking at this downward trend from another perspective, 55% of the large spills recorded occurred in the 1970s, and this percentage has decreased each decade to 7% in the 2000s (Figure 2).

A decline can also be observed with medium sized spills (7-700 tonnes) in Figure 4 and Table 2. Here, the average number of spills in the 2000s was close to 15, whereas in the 1990s the average number of spills was almost double this number.

No large spills were recorded for 2012 but 7 medium spills were recorded. Despite being higher than those seen in 2010 and 2011, this figure is still far below the averages for previous decades (Figure 3 and Table 2).

 

 

 

Figure 3: Number of large spills (> 700 tonnes) from 1970 to 2012

(Download a PDF version of Figure 3 (308Kb))

 

Figure 4: Number of medium sized (7-700 tonnes) and large (>700 tonnes) spills per decade from 1970-2012

 

 

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Quantities of Oil Spilt

The vast majority of spills are small (i.e. less than 7 tonnes) and data on numbers and amounts is incomplete due to the inconsistent reporting of smaller incidents worldwide.

Reports on spills of 7 tonnes and above tend to be more reliable and information from these is included in the database to give a series of annual estimates of the total quantity spilt for the years 1970-2012. These amounts are rounded to the nearest thousand. Inconsistencies may occur between sums of each year and totals for the decade.  However, all percentages and averages have been calculated using unrounded figures.

Approximately 5.75 million tonnes of oil were lost as a result of tanker incidents from 1970 to 2012. However, as Figures 5 and 6 indicate, the volume of oil spilt from tankers demonstrates a significant improvement through the decades. Consistent with the reduction in the number of oil spills from tankers, the volume of oil spilt also shows a marked reduction. For instance, from Table 3 it is interesting to observe that an amount greater than the total quantity of oil spilt in the decade 2000 to 2009 (212,000 tonnes) was spilt in several single years in earlier decades.

The total amount of oil lost to the environment in 2012 is the lowest on record so far; with 7 medium spills this equates to an average of approximately 100 tonnes per incident (Table 3 and Figure 6).

 

Figure 5: Oil spilt per decade as a percentage of the total spilt between 1970 and 2009

 

Figure 6: Quantities of oil spilt > 7 tonnes, 1970 to 2012

(spill size rounded to nearest thousand)

(Download a PDF version of Figure 6 (273Kb))

 

Large spills

As demonstrated in Figures 6 and 7, when looking at the frequency and quantities of oil spilt, it should be noted that a few very large spills are responsible for a high percentage of oil spilt. For example, in more recent decades the following can be seen:

• In the 1990s there were 360 spills over 7 tonnes, resulting in 1,135,000 tonnes of oil lost; 73% of this amount was spilt in just 10 incidents.
• In the 2000s there were 182 spills over 7 tonnes, resulting in 212,000 tonnes of oil lost; 54% of this amount was spilt in just 4 incidents.

The figures for a particular year may therefore be severely distorted by a single large incident. This is clearly illustrated by incidents such as ATLANTIC EMPRESS (1979), 287,000 tonnes spilt; CASTILLO DE BELLVER (1983), 252,000 tonnes spilt and ABT SUMMER (1991), 260,000 tonnes spilt.

 

Figure 7: Spills > 7 tonnes per decade showing the influence of a relatively small number of comparatively large spills on the overall figure

 

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Seaborne Oil Trade

Apart from a fall in the early 1980s during the worldwide economic recession, seaborne oil trade has grown steadily from 1970 (Figure 8). While increased movements might imply increased risk, it is encouraging to observe however that downward trends in oil spills continue despite an overall increase in oil trading over the period.

Figure 8: Seaborne oil trade and number of tanker spills > 7 tonnes, 1970-2011

(crude and oil product*)

*Product vessels of 60,000 DWT and above

 

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Causes of Spills

The causes and circumstances of oil spills are varied, but can have a significant effect on the final quantity spilt. The following analysis explores the incidence of spills of different sizes in terms of the operation that the vessel was undertaking at the time of the incident and the primary cause of the spill. For small and medium sized spills, operations have been grouped into Loading/Discharging, Bunkering, Other Operations and Unknown Operations. Other Operations includes activities such as ballasting, de-ballasting, tank cleaning and when the vessel is underway.

Reporting of larger spills tends to provide more information and greater accuracy, which has allowed further breakdown of vessel operations. Therefore, operations for larger spills have been grouped into Loading/Discharging, Bunkering, At Anchor (Inland/Restricted waters), At Anchor (Open water), Underway (Open water), Underway (Inland/Restricted waters), Other Operations and Unknown Operations. The primary causes have been designated to Allisions/Collisions, Groundings, Hull Failures, Equipment Failures, Fire and Explosion, and Other/Unknown.  Other causes include events such as heavy weather damage and human error. Spills where the relevant information is not available have been designated as Unknown.

Small and medium sized spills account for 95% of all the incidents recorded; a large percentage of these spills, 40% and 29% respectively, occurred during loading and discharging operations which normally take place in ports and oil terminals (Figures 9 and 12).  While the cause of these spills is largely unknown it can be seen that equipment and hull failures account for approximately 46% of these incidents for both size categories (Figures 11 and 14). Nevertheless, when considering other operations there is a significant difference in the percentage of allisions, collisions and groundings between these two size groups where we see the percentage increasing from 2% for smaller spills to 39% for medium spills (Figures 11 and 14).

Large spills account for the remaining 5% of all the incidents recorded and the occurrence of these incidents has significantly decreased over the past 43 years. From Figure 15, it can be seen that 50% of large spills occurred while the vessels were underway in open water; allisions, collisions and groundings accounted for 59% of the causes for these spills (Figure 17). These same causes account for an even higher percentage of incidents when the vessel was underway in inland or restricted waters, being linked to some 95% of spills. Restricted waters include incidents that occurred in ports and harbours.

Perhaps unsurprisingly activities during loading or discharging result in significantly more small or medium sized spills than large spills. However, large spills do still occur during loading and discharging, and from Figure 17 and Table 6, it can be seen that 59% of these incidents are caused by fires, explosions and equipment failures.

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Figure 9: Incidence of spills <7 tonnes by operation at time of incident, 1974-2012

Figure 10: Incidence of spills <7 tonnes by cause, 1974-2012

Figure 11: Incidence of spills <7 tonnes by operation at time of incident and primary cause of spill, 1974-2012

 

	Operations
	Loading/ Discharging	Bunkering	Other Operations	Unknown	Total
	3157	564	1281	2842	7844
Causes
Allision/Collision	1	2	13	166	182
Grounding	2	0	14	226	242
Hull Failure	324	10	47	196	577
Equipment Failure	1124	104	251	202	1681
Fire/Explosion	50	5	35	83	173
Other	842	289	517	163	1811
Unknown	814	154	404	1806	3178
Total	3157	564	1281	2842	7844

Table 4: Incidence of spills <7 tonnes by operation at time of incident and primary cause of spill, 1974-2012

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Figure 12: Incidence of spills 7-700 tonnes by operation at time of incident, 1970-2012

 

Figure 13: Incidence of spills 7-700 tonnes by cause, 1970-2012

Figure 14: Incidence of spills 7-700 tonnes by operation at time of incident and primary cause of spill, 1970-2012

 

	Operations
	Loading/ Discharging	Bunkering	Other Operations	Unknown	Total
	390	33	150	777	1350
Causes
Allison/Collision	4	0	38	308	350
Grounding	0	0	22	251	273
Hull Failure	36	4	11	48	99
Equipment Failure	143	6	17	38	204
Fire/Explosion	8	0	13	24	45
Other	96	14	33	26	169
Unknown	103	9	16	82	210
Total	390	33	150	777	1350

Table 5: Incidence of spills 7-700 tonnes by operation at time of incident and primary cause of spill, 1970-2012

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Figure 15: Incidence of spills >700 tonnes by operation at time of incident, 1970-2012

 

Figure 16: Incidence of spills >700 tonnes by cause, 1970-2012

 

Figure 17: Incidence of spills >700 tonnes by operation at time of incident and primary cause of spill, 1970-2012 (One bunkering incident occurred in this size category but has not been included in this figure)

 

	Operations
	At anchor (Inland/ Restricted)	At anchor (Open Water)	Underway (Inland/Restricted)	Underway (Open Water)
	14	9	82	227
Causes
Allision/Collision	6	5	33	66
Grounding	4	2	45	68
Hull Failure	1	1	0	50
Equipment Failure	0	0	0	6
Fire/Explosion	1	1	3	25
Other	2	0	1	11
Unknown	0	0	0	1
Total	14	9	82	227

 

	Operations cont...
	Loading/ discharging	Bunkering	Other operations/unknown	Total
	41	1	81	455
Causes
Allision/Collision	1	0	23	134
Grounding	2	0	28	149
Hull failure	0	0	8	60
Equipment failure	11	0	1	18
Fire/Explosion	13	1	9	53
Other	8	0	6	28
Unknown	6	0	6	13
Total	41	1	81	455

Table 6: Incidence of spills >700 tonnes by operation at time of incident and primary cause of spill, 1970-2012

 

If you would like to receive PowerPoint slides of any of the graphs used above, please contact Deborah Ansell (deborahansell@itopf.com).

Further information is available in:

Trends in Oil Spills from Tankers and ITOPF non-Tanker Attended Incidents [600Kb]

by Susannah Musk

Paper presented at the 2012 Arctic and Marine Oilspill Program (AMOP) Technical Seminar, 5-7 June 2012, Vancouver Canada

Trends in Oil Spills from Tanker Ships 1995-2004 (2005) [603kb]

by Keisha Huijer
Paper presented at the 28th Arctic and Marine Oilspill Program (AMOP) Technical Seminar, 7-9 June 2005, Calgary, Canada

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