No.

Conditions with initial filings due prior to commencing construction, or prior to

commencing construction of specified Project component(s)

CPCN

OC2

OC49

Temp

Pump1

Pump2

Tanks

Deact

National Energy Board

424

22

Updated terminal risk assessments

Trans Mountain must file with the NEB for approval,

at least 6 months prior to

commencing construction, and at the same time as Trans Mountain’s filings for

Conditions 23, 24 and 25

, updated risk assessments for the Edmonton Terminal West

Tank Area, the Sumas Terminal, and the Burnaby Terminal. The updated risk assessments

must quantify and/or include the following:

a) the effect of any revised spill burn rates ;

b) the potential consequences of a boil-over;

c) the potential consequences of flash fires and vapour cloud explosions;

d) the cumulative risk based on the total number of tanks in the terminal, considering

all potential events (pool fire, boil-over, flash fire, vapour cloud explosion);

e) the domino (knock-on) effect caused by a release of the contents of one tank on

other tanks within the terminal’s common impoundment area(s), or other tanks in

adjacent impoundment areas; and

f) risk mitigation measures, including ignition source control methods.

For those risks that cannot be eliminated, Trans Mountain must demonstrate in each

risk assessment that mitigation measures will reduce the risks to levels that are As

Low As Reasonably Practicable (ALARP) while complying with the Major Industrial

Accidents Council of Canada (MIACC) criteria for risk acceptability.

The quantitative risk analysis must be based on recognized methodology, models, and

software. Product release frequencies and event probabilities must be based on recent,

documented data sources. The effect of mitigation measures on the risk results must be

justified and documented.

X

23

Secondary containment – Edmonton Terminal

Trans Mountain must file with the NEB for approval,

at least 6 months prior to

commencing construction

, the final design of the Edmonton Terminal West Tank

Area, including a report demonstrating the following:

a) the drainage system’s capability to rapidly and safely channel a significant

release from any tank in the West Tank Area Common Impoundment to the

Remote Impoundment Annex and Remote Impoundment at the same time that

a design precipitation event is occurring, without overtopping the diked areas.

b) the adequacy of the design in mitigating the following consequences of an

accidental release and/or ignition of hydrocarbons, both within and beyond the

Edmonton Terminal property boundary:

i)

harm to personnel and the public;

ii) environmental damage; and

iii) damage to facilities; and

c) the ability of the Common Impoundment, Remote Impoundment Annex, and

Remote Impoundment to contain a release of hydrocarbons from a rupture of

the largest tank within the West Tank Area concurrent with a 1-in-100 year, 24-

hour storm event. The scenario must include an allowance for water generated

from potential firefighting activities and the maximum potential amount of

standing water in all areas of the secondary containment system.

X