Statistics

 

 

 

Downward Trend in Spills is Maintained Despite Blip

 

ITOPF's tanker spill statistics released today showed a slight increase in the number of large spills from tankers in 2013 compared to the previous two years but the downward trend is maintained.

Although the volume of oil spilt is also up on the last two years, the total quantity spilt so far this decade is only a sixth of that spilt for the same period in the previous decade.

Three oil spills of 700 tonnes or more occurred last year with one incident accounting for the vast majority of the total. In October the MT YONG WIN 3 reportedly capsized and sank spilling an estimated 5,000 tonnes of diesel oil. Two other incidents resulted in a spill of about 1,000 tonnes of fuel oil and 800 tonnes of bitumen respectively. These incidents illustrate the unpredictability of spills and the importance of preparing to respond to the range of oils involved.

A Chinese version of the statistics package is also available (1 Mb)

14th January 2014

 

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, their insurers and ITOPF's own experience at incidents. 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 often 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. While we strive to maintain precise records for all spill information, we cannot guarantee that the information taken from the shipping press and other sources is complete or accurate. Fom time to time, data is received after publication and, in which case, adjustment to previous entries may be 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 (5MB) of the following information is available in Adobe Acrobat. Hard copies are also available, please contact Terry Goodchild (terrygoodchild@itopf.com).

A version is also available in Chinese (1 Kb)

For further information on ITOPF's tanker spill statistics, please contact Susannah Musk, Technical Support Coordinator (susannahmusk@itopf.com).

If you would like to receive PowerPoints of the graphs below, please contact Deborah Ansell, Information Officer (deborahansell@itopf.com).

 

 

Return to top

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; it is of note that 19 of the largest spills recorded occurred before the year 2000. 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 AEGEAN SEA 1992 La Coruna, Spain 74,000
16 SEA EMPRESS 1996 Milford Haven, UK 72,000
17 KHARK 5 1989 120 nautical miles off Atlantic coast of Morocco 70,000
18 NOVA 1985 Off Kharg Island, Gulf of Iran 70,000
19 KATINA P 1992 Off Maputo, Mozambique 67,000
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 (quantities have been rounded to nearest thousand)

 

Figure 1: Location of major spills (click map to view larger version in PDF format (824Kb))

 

Return to top

 

Number of Incidents and Quantity Spilt

Large spills as a percentage of those recorded from 1970-2009 per decade

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 (>700 tonnes) 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 has decreased significantly in the last 44 years during which records have been kept. The average number of major spills for the decade 2000-2009 is 3.5, one seventh of the average for years in the 1970s. Looking at this downward trend from another perspective, 54% of the large spills recorded occurred in the 1970s, and this percentage has decreased each decade to 8% 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.

Three oil spills of 700 tonnes or more occurred last year with one incident accounting for the vast majority of the total. In October the MT YONG WIN 3 reportedly capsized and sank spilling an estimated 5,000 tonnes of diesel oil.  Two other incidents resulted in a spill of fuel oil and bitumen. These incidents illustrate the unpredictability of spills and the importance of preparing to respond to the range of oils that can be spilt. In addition, four medium spills of various oil types were recorded, resulting in a total of seven spills recorded of at least 7 tonnes. This figure is still far below the averages for previous decades and is in line with the trend of the last three years (Figure 3 and Table 2).

 

 

Table 2: Number of spills over 7 tonnes
Show/Hide

 

Number of large spills

Figure 3: Number of large spills (> 700 tonnes) from 1970 to 2013

(Download a PDF version of Figure 3 (154Kb))

 

Number of medium and large spills

Figure 4: Number of medium sized (7-700 tonnes) and large (>700 tonnes) spills per decade from 1970-2013 (only 4 years of data for the period 2010-2013)

 

 

Return to top

Quantities of Oil Spilt

The vast majority of spills are small (i.e. less than 7 tonnes) and data on the numbers of incidents and quantity of oil spilt 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 1970-2013. These quantities are rounded to the nearest thousand. Inconsistencies may occur between the sums of each year and the totals.  However, all percentages and averages have been calculated using unrounded figures.

Approximately 5.74 million tonnes of oil were lost as a result of tanker incidents from 1970 to 2013. 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 (213,000 tonnes) was spilt in several single years in earlier decades.

The total amount of oil lost to the environment in 2013 was 7,000 tonnes, the vast majority of which can be attributed to the three large spills (>700 tonnes) recorded during the year (Table 3 and Figure 6).

Oil spilt per decade

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



Table 3: Annual Quantity of Oil Spilt
Show/Hide

 

Quantities of oil spilt > 7 tonnes

Figure 6: Quantities of oil spilt > 7 tonnes, 1970 to 2013 (rounded to nearest thousand)

(Download a PDF version of Figure 6 (177Kb))

 

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 358 spills of 7 tonnes and over, resulting in 1,133,000 tonnes of oil lost; 73% of this amount was spilt in just 10 incidents.
• In the 2000s there were 182 spills of 7 tonnes and over, resulting in 213,000 tonnes of oil lost; 53% of this amount was spilt in just 4 incidents. 

• In the four year period 2010-2013 there have been 28 spills of 7 tonnes and over, resulting in 22,000 tonnes of oil lost; 90% of this amount was spilt in just 8 incidents.

Therefore, the figures for a particular year may 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 6).

 

Spills > 7 tonnes per decade

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

 

Return to top

 

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.

Seaborne oil trade and number of tanker spills

Figure 8: Seaborne oil trade and number of tanker spills > 7 tonnes, 1970-2012

(crude and oil product*)

*Product vessels of 60,000 DWT and above. Barges excluded.

 

Return to top

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 45% 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 44 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 98% 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 57% of these incidents are caused by fires, explosions and equipment failures.

 

Incidence of spills <7 tonnes by operation

Figure 9: Incidence of spills <7 tonnes by operation at time of incident, 1974-2013

 

Incidence of spills < 7 tonnes by cause

Figure 10: Incidence of spills <7 tonnes by cause, 1974-2013

 

Incidence of spills < 7 tonnes by operation at time of incident and primary cause of spill

  Figure 11: Incidence of spills <7 tonnes by operation at time of incident and primary cause of spill, 1974-2013

 

Operations

Loading/

Discharging

Bunkering
Other Operations
Unknown
Total
3158
565
1282
2842
7847
Causes
Allision/Collision
2
2
14
167
185
Grounding
2
0
14
224
240
Hull Failure
324
10
47
195
576
Equipment Failure
1125
104
251
202
1682
Fire/Explosion
50
5
35
83
173
Other
841
290
517
164
1812
Unknown
814
154
404
1807
3179
Total
3158
565
1282
2842
7847

Table 4: Incidence of spills <7 tonnes by operation at time of incident and primary cause of spill, 1974-2013


Return to top

Incidence of spills 7-700 tonnes by operation at time of incident

Figure 12: Incidence of spills 7-700 tonnes by operation at time of incident, 1970-2013

 

Incidence of spills 7-700 tonnes by cause

Figure 13: Incidence of spills 7-700 tonnes by cause, 1970-2013

 

Incidence of spills 7-700 tonnes by operation at time of incident and primary cuase of spill

Figure 14: Incidence of spills 7-700 tonnes by operation at time of incident and primary cause of spill, 1970-2013

 

Operations

Loading/

Discharging

Bunkering
Other Operations
Unknown
Total
391
32
169
759
1351
Causes
Allison/Collision
5
0
51
298
354
Grounding
0
0
25
246
271
Hull Failure
36
4
14
46
100
Equipment Failure
142
6
17
38
203
Fire/Explosion
8
0
13
25
46
Other
98
13
35
25
171
Unknown
102
9
14
81
206
Total
391
32
169
759
1351

Table 5: Incidence of spills 7-700 tonnes by operation at time of incident and primary cause of spill, 1970-2013

Return to top

 

Incidence of spills >700 tonnes by operation

Figure 15: Incidence of spills >700 tonnes by operation at time of incident, 1970-2013

 

Incidence of spills > 700 tonnes by cause

Figure 16: Incidence of spills >700 tonnes by cause, 1970-2013

 

Incidence of spills >700 tonnes by operation at time of incident and primary cause of spill

Figure 17: Incidence of spills >700 tonnes by operation at time of incident and primary cause of spill, 1970-2013 (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)
15
10
80
228
Causes

Allision/Collision

6
5
33
66
Grounding
5
2
45
68
Hull Failure
2
1
0
49
Equipment Failure
0
0
0
6
Fire/Explosion
1
2
2
25
Other
1
0
0
13
Unknown
0
0
0
1
Total
15
10
80
228

 

Operations cont...

Loading/

discharging

Bunkering
Other operations/unknown
Total
42
1
83
459
Causes

Allision/Collision

2
0
24
136
Grounding
2
0
28
150
Hull failure
0
0
8
60
Equipment failure
11
0
1
18
Fire/Explosion
13
1
8
52
Other
8
0
7
29
Unknown
6
0
7
14
Total
42
1
83
459

Table 6: Incidence of spills >700 tonnes by operation at time of incident and primary cause of spill, 1970-2013

 

 

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

Return to top