REVIEW OF THE CONCORD REPORT 3.1 Basis of the Concord Report

The purpose of the Report developed by Concord Scientific

Corporation (Concord Report) is to study the public risks associated with the marine transport of liquified gas, including the docking facilities associated with such transport. (Concord Report, at 1-I) The stated concern is thermal radiation and fire; the adverse health end-point is acute fatalities only. (Concord Report, at 2-10)

The approach developed by Concord establishes mathematical

definitions of risk, adopts models to describe heavy gas diffusion- dispersion and the initiation of fires, uses other models, including an exposure-response function. Concord applies those models to determine the public risks from several scenarios potentially associated with the operation of the Soligaz docking facility, and quantitative estimates of public risks and provides appropriate references to its risk assessment.

The following summarizes the principal areas of the Concord Report findings developed in this Review. Additional comments are provided in the section called Additional Discussion: The envelope of risks. appropriate measure should be the “conditional joint distributions”

for example in the analysis of an accident during transit and a

“reasonably well established engineering techniques.” (Concord Report, at 2-10) These techniques apparently include the use of fault trees, event-trees, and other standard techniques from

reliability analysis to identify and assess risks. There are, however, no references to the direct use of these methods.

The modeling, by diffusion- dispersion, of the airborne transport of released LNG/LPG conforms with the state-of-the-art of risk

assessment methods as applied to dense cloud transport. The assumption that the fire hazard from flashes (50% of the lower limit of flammability of propane) also is reasonable and protective of public health. The thermal radiation mode1 is recent and

appropriate; however, the analysis should probably include secondary fires, or at least provide the rationale of why these fires apparently

have not been taken into consideration.

The probit analysis, the exposure-response relationship for the adverse health outcomes associated with fire is appropriate and consistent with the literature studied and reported in this Review, in the second Appendix.

The representation and calculation of societal risk is appropriate but does not include measures of variability or uncertainty. It is

meteorology, and includes river sector lengths and time-to-transit. probabilistic risk assessment. It is, however, limited. Fore example, the analyses developed in this section of the Concord Report are

performed. (Concord Report, at 4-9) Simulation, including stochastic analysis, cari be used to at least bound the uncertainty about the potential risks associated with accidents involving this type of LNGILPG carrier.

high-angle-of-attack collisions. The asserted result that the

discussed. Fortunately, the risk assessment includes the scenario of a high angle of impact collision.

Other events that cari lead to spills are also discussed and include on-board explosions, fires, mechanical failures, and SO on. (Concord Report, at 4-4) Although the discussion is terse, the possible

scenarios seem to be representative. What requires additional discussion is why the reliance on anecdotal information from one individual alone should be sufficient for the part of the risk

assessment that relies on such information.

The spills from the docking area is assumed to consist of a 100 cubic meters, instantaneously spilled. This is not well documented and there are no references either to support this statement or to Varennes, are derived from historical accident statistics from worldwide carrier data. Although this data is certainly valuable, it

Conseauence Assessment

The analyses included in this section are plausible -- they depend on the previous assumptions and models described both in the main section of the Concord Report and in the Appendices included there.

The comparisons of the final results -- using the complement of the cumulative frequency distribution -- is acceptable and clearly puts the results into perspective. However, the uncertainty about the risk profiles developed by Concord should be shown and compared to the uncertainty in the other risk profiles.

Conclusions

The Concord Report is acceptable. However, it does not attempt to be a comolete treatment -- perhaps because of the limitation of the tasks required for Concord to accomplish and possible accord with regulatory requirements -- of the potential risks associated with the aspects of the Soligaz facility studied by Concord. Moreover, the Report is uncritical of the issues of the measures of risk adopted in the analysis.

The risk assessment itself is satisfactorv. It requires, however, additional description of the uncertainty affecting the data and the models used in the assessment of its two ares of concern. It also requires that Concord develoo the uncertaintv about the comolement gf the freauency distributions. and the risk isooleths it has

developed.

A more problematic issue is the use of a single health end-point -- prompt fatalities. Concord must address the question of whether the Iow risks it has calculated would increase if delaved deaths, iniuries. and the effect of smoke inhalation were taken into account.

4.0 ADDITIONAL DISCUSSION: The envelope of risks

This section of the Review provides additional comments on the Geostock and the Concord Reports in terms of their inclusions and

exclusions insofar n rned. The risks

determined by Geostock and by Concord are concerned with the following systems:

1. Geotechnical characteristics of the underground reservoirs -- Geostock Report.

2. Hydrogeologic characteristics of the reservoirs -- Geostock Reoort.

3. Wellheads -- Geostock Report.

4. Piping, by location, and their characteristics -- Geostock Report.

5. Surface facilities for receiving, temporary storage, and shipping propane, butane and LNG for: marine carriers, trucks, railroad cars, and pipeline -- Geostock Report.

6. Water treatment systems -- Geostock Report.

7. Marine transport of LPGs via carriers, including only port

operations related to the unloading of these products to the terminal facilities on the Soligaz site-- Concord Report.

4.1 Geostock Report: Envelope of Events

The Geostock Report -- specialized to the land-based facilities of Soligaz -- has assessed spills and other releases of gasses resulting from the following classes of events:

1. Piping and equipment corrosion, 2. Valve-related failures,

3. Joint-related failures,

5. Various accidents sequences, e.g., at the wellhead and other state-of-the-art of practical risk assessments. Seismic risk is cursorily discussed. Although it appears that Geostock has studied seismic risk, it is not clear what are the factors of safety for establish response behavior under peak around acceleration, and account for such components as spectral content. The appropriate probabilistic considerations should be discussed in some detail.

Geostock should also clarify whv the historical record determines the design basis earthquake, provide information on the regulatory requirements for any such design basis, and comment on whether the design basis is sufficient for the Soligaz facility. The issue that should be discussed, is the joint occurrence of a design basis earthquake and other adverse events, such as unloading gas.

The information on wind velocities should include both rotational and translational speeds, as well as the difference in pressure in the

less probable -- outcomes. Even if the magnitude of a particular

completeness requires a more extensive assessment.

The “levels of severity” developed by Geostock bound some of the events and are generally conservative. What is not clear, however, is the amouni of conservatism inherent to the hypotheses formulated by Geostock since the hypotheses are given without full discussion. citation provided by Geostock, requires that the developer should identifv and evaluate the risks associated with the ooerations of

hypothesized. Specifically, the events developed by Geostock do not exclude a oriori scenarios which may not have been experienced by

are de minimis or not.

This is not to say that completely random and extremely rare events, such as meteorite strikes, necessarily should be taken into

consideration to develop the envelope of risks from the Soligaz facility. The issue is that the cases developed by Geostock may be self-limiting, although realistic and conservative. It is incumbent on Geostock to show whether other cases should be considered, and that the outcomes from those omitted cases are unlikely and thus should be excluded from further consideration.

There is no rationale given for the choices made, other than

Geostock’s own experience. However competent Geostock may be, it is not omniscient. The aura of infallibility taken in their Report is inappropriate and counterproductive. It is inappropriate because human lives cari be lest; it is counterproductive because risk assessment primary objective is to help dealing with the

unexpected. Geostock’s approach both minimizes the contribution that risk assessment makes properly to bound the danger of the Soligaz facility, and introduces limitations to their risk

assessment. There should be a detailed discussion -- including

the danger is limited to the areas of “stockage”-- on site -- and The Geostock Report is incomplete. Its principal deficiencies are that it is uncritical of its own methodology and that it excludes the respectively, recognizing that LPG carriers cari carry LNG.

The historical data for carao spills from LNG carriers,

approximately 11 years, serve as part of the basis for developing the

data base does not allow to determine the conditions under which a cargo spill cari occur. (Concord Report, at 4-3)

The risks from collisions at high angle-of-attack, resulting in pills on the St. Lawrence river nearby populated centers, were determined from discussions with Capt. Iskandar of Liquidtransport. (Concord

Report, at 4-3) This information is not sufficient because it is not clear hpw this information was validated. Interviews with Coast- Guard officers and other experts should also be provided. This is an adverse outcomes depend on the physical and chemical conditions present when gas is released. The Concord Report focusses on the flash fire and pool fire; other fires and explosions are not discussed because they do not appear to be “credible.” Credibility is in the eye of the beholder: more discussion of a Concord believes that other adverse events are not credible is required.

according to the citations -- have not appeared in peer-reviewed journals. The methods used by Concord are provided in their Report:

they seem appropriate, but their assumotions are not sufficiently discussed.

4.2.2 Carrier-Related Spills: Case (Scenario) Development The on-board accidental events that cari lead to spills were in part developed from discussions with two experts. Apparently, the worst release associated with those on-board events would be the rapid minutes. Additionally, the remaining 10,000 cubic meters would be spilled in 5 hours, under the assumption that the bulkhead valve

assessment. The scenario of a collision at higher than expected

4.2.3 Land Facilities: Scenario Development

The development of scenarios for the risk assessment performed by Concord excludes “... facilities beyond the transfer system...”

(Concord Report, at 4-5) The assessment of the scenario leads to the

4.2.4 Population Exposure and Meteorology

Population exposure assessment should reflect the &XIoaraohy of the area and not only the magnitude of the population. Thus, for instance, it is important to know ground elevations, as well as population density and size. The effect of considering topography changes the overall risks for both fatalities and injuries.

The rationale for choosing three reoresentative locations is not sufficiently detailed ta decide if these three locations are tTUly

least to bound the effect of severe weather

4.2.5 Comments on the Methods to Assess Risks

The bounding of the risks clearly shows that the 20,000 ms release is much more significant than any other release. Thus, the crucial issue is the reasonableness of this assumption. This issue requires additional clarification. Aside from this clarification, it appears that the Concord Report provides reasonable estimates of public risks from the adverse events considered: namely, the two types of fires.