KM – Risk Analysis

These are the Letters of Comment submitted to the National Energy Board (NEB).

  1. Letter Of Comment Evaluation of risks associated with the Kinder Morgan project, Oct 2014
  2. Letter of Comment, July 2015

Evaluation of risks associated with the Kinder Morgan project

By Ricardo O.Foschi, P.Eng
October 2014


Kinder Morgan presents calculated return periods (in years) for oil spills of different volumes. These are given in Table 34 of their TERMPOL Report 3.15. The oil spills result from marine accidents or incidents.

By definition, the return period is an estimation of the average time elapsed between spills of a given volume. As such, approximately 50% of the spills would occur before the return period and 50% would occur after that time; therefore, the return period is not a good statistic to communicate probability of a spill. Of importance is the probability that at least one spill, of a given volume, would occur within the operating life of the project. The calculation of such a probability is straightforward given the return period and the operating life.

Table 1 below shows the results of this calculation, starting from the Kinder Morgan estimations.


The above Table permits the following conclusions:

  • With no mitigations the probabilities of at least one oil spill in 50 years are too high. Thus, mitigations are essential and must be enforced.
  • Even with mitigations, probability of at least one oil spill in 50 years, greater than 8,250 cubic meters, is deemed to be too high (0.10 or 10%). This is comparable to the probability for a spill greater than 5,000 m3 calculated for Northern Gateway (9%). The probability for a large spill of16,500 m3 is more tolerable (0.02 or 2%), but even a more moderate spill would cause very substantial damage.
  • Even with mitigations, there is a 19% probability of an oil spill, regardless of volume. This is also too high.


The methodologies for the determination of the probability of collision of a vessel with a bridge pier are specified both in the American AASHTO Code (1991) as well as in the Canadian CSA‐S6‐00 (2000). Both Codes essentially contain the same provisions, differing in the system of units used in the prescribed equations. The methodology followed here agrees with that which is specified in the Canadian Code CSA‐S6‐00. This methodology has been used to evaluate the risk of collisions with several new bridges across the Fraser River: Golden Ears, Pitt River, Port Mann and the Skytrain Canada Line.

The methodology is based on the estimation of:

PA = probability of aberrancy, or the probability that a vessel will be out of control or likely to be involved in a collision incident;

PG = conditional, geometric probability that a vessel will collide with a pier, given that the vessel is out of control or likely to be involved in a collision.

The product PE = PAPG gives the probability that a collision will take place, which has to be modified according to the number N of vessels transiting per year or in any interval T. From historical accident data in US waterways, the Code gives the value PA= 0.6 x 10‐4, applicable to ships.
The geometric probability is calculated considering that the position of the ship in distress is randomly located, with a mean equal to 0.0 (the centerline of the navigation channel) and a standard deviation equal to the length Ls of the vessel. This random position s is assumed to obey a Normal distribution. If mitigation aids from tugs were present, then the standard deviation of the position s would be smaller. For perfect mitigation, the tugs would keep the vessel along the centerline of the channel. In the calculations shown here it is assumed that the standard deviation could be a value (Ls / r), with r
being a factor either 1, 2, 4 or 6. Thus, r = 6 would imply a more effective mitigation by the intervention
of tugs.

The probability PE is finally corrected for the number of vessels transiting the bridge location per year
(here assumed to be 600), and then for the period of operations T = 50 years.

The vessel considered is an Aframax tanker, with a length of 245m and a beam of 34m. The opening of the central span of the highway Second Narrows Bridge is 350m.

Results are show in the following Table 2:


It can be concluded from these results, that the probability of at least one collision with the bridge, over
50 years of operation and at 600 vessels per year, must be mitigated by the use of tugs. This is essential and must be enforced. With proper and effective mitigation, it would appear that collision with the bridge could have a low probability of occurrence.
Collision with the bridge does not necessarily mean major damage or collapse of the structure, nor an oil
spill. However, damage to the bridge would result in interruptions of traffic flow with associated economic consequences. Collapse of the bridge or substantial damage could be studied, but it would require a detailed structural analysis of the bridge and its footings.

  •  A more comprehensive model should be studied to relate the factor r to the tug intervention policy.
  • These results apply to the highway Second Narrows or Ironworkers Memorial Bridge. The situation for the railroad bridge would be more risky, given that the channel between the bridge towers is much smaller than 350m. For this bridge it would be even more essential to provide an effective mitigation policy.

Letter of Comment to NEB Regarding TMX

We are a group of Concerned Registered Professional Engineers (CPE).  We have extensive experience in the design, operation and maintenance of resource export terminals, design of escort tugs, handling of ships and navigation.  We wish to make it clear that we are not unconditionally opposed to the shipment of Canadian resources overseas, since we generally have an ample supply in Canada.


While the export of resources is a vital part of our economy, we believe that exporting must be done in an environmentally sensitive manner; safeguarding a sustainable future for next generations.  We have examined the marine aspects of the Trans Mountain Expansion (TMX) project and found that their plan to increase the transport of Diluted Bitumen (Dilbit) from their existing terminal in Burnaby, through the Port of Vancouver, the Straits of Georgia and Juan de Fuca and to the Pacific Ocean, presents a high risk to the environment and to infrastructure located along these routes.


Our purpose in writing this Letter of Comment (LOC) on the Trans Mountain Expansion Project is twofold, as described in what follows:


  • The risks of an accident and a bad Dilbit spill, as submitted by TMX resulting from the increased tanker traffic, are considerable. Trans Mountain’s own experts show estimations of risk associated with different spill volumes, and do so in terms of “return periods”.  These are average expected times between spills, and are generally long, as shown in their TERMPOL Report 3.15 (Table 34), of November 25, 2013.  This manner of reporting results is misleading and presents an over-optimistic picture for the general public.  In fact, the return periods shown in the TERMPOL Report are mathematically equivalent, for example, to a ten percent (10%) probability that a spill of 8.25 million or more litres will occur in a 50 year operating period, even taking into account all the proposed mitigation strategies (use of escort tugs).  This is considerably greater than the mitigated spill risk of nine percent (9%) for a spill of 5.0 million or more litres estimated for the Northern Gateway project out of Kitimat.  The TMX probability of at least one spill in 50 years increases to 19% when spills of any size are considered.  These probabilities over a 50-year operating window are clearly unacceptable. Concerned Professional Engineers (CPE) does not have access to the model that Kinder Morgan’s experts Det Norske Veritas (DNV) used to predict the probability of spills but believe that this model should be made available and a completely independent analysis of the spill risk should be carried out.


  • We also want to point out that there has not been an analysis done of the potential for a collision of a fully loaded or an empty Aframax-type tanker with either the First or the Second Narrows bridges, particularly with the present Second Narrows railway and highway bridges. If these bridges were to be built after implementation of the TMX project, they would have to satisfy the safety standards for vessel collision prescribed in the Canadian S6 Highway Bridge Code.  The requirements of S6 should not be disregarded because the bridges are already there.  The Aframax is a medium-sized crude tanker with a dead weight tonnage (DWT) ranging between 80,000 and 120,000 Tonnes and a length of 245 metres.  The regional economic consequences of bridge(s) damage (or collapse) following a collision accident cannot be over-emphasized; whether the collision triggers a spill or not.  The history of collisions of vessels with these bridges needs to be carefully analyzed and re-evaluated with regard to the proposed TMX traffic.  This review should include the number of times the railway bridge has been knocked out of service for a considerable amount of time and the number of times that it has had to be completely replaced.  We believe that when this analysis is done, the risks will probably be considerably higher than those stated by Kinder Morgan’s experts.

We find that the risk of collision is highly dependent on the effectiveness of tugboats.  Thus, the proponents should have presented a detailed modelling of the interaction dynamics of the system tanker-tugboats, showing the degree of control that the tugboats can achieve under different scenarios.  We are aware for example, that similar studies have been carried out by the City of Seattle for tanker traffic in Puget Sound and by San Francisco for similar traffic in Northern San Francisco Bay.  We find that the proponent’s assessment of effectiveness of tugboat assistance is based on subjective input and not on a quantitative evaluation.  As such, it falls short of the needs associated with the risk analysis for a project with high consequences.


We ask therefore, that prior to NEB deciding on whether or not to give approval to the project, they should consider the above points and demand results from corresponding studies, analyses and modelling in order to carefully review them.


As stated at the beginning of this letter, CPE believe that the export of resources is a vital part of our economy.  However, we also believe that we have to carry out this export in the safest way possible.  Allowing the TMX through Burrard Inlet from its present terminal is not the safest alternative.  There are much safer alternative ports around the Lower Mainland that can easily connect to the proposed pipeline.  They just cost more money to build.  CPE feels that the increase in safety and the decrease in risk demands that NEB carefully evaluate the risks involved, before making a recommendation to proceed with TMX as it is presently proposed.


For further detail about our assessment of risk please see our earlier October 2014 Letter of Comment to NEB shown on our website:


Brian Gunn

Spokesperson for CPE