McGill Faculty of Law: Extra-Contractual Obligations/Torts: Prof. Lara Khoury, 2002-03/Summary by Derek McKee
Now that we’ve assessed causation, and we are left with multiple faults, what do we do?
If the causes and injuries can be divided, liability will be divided.
If the causes and injuries can’t be divided, There are several possibilities:
distinct and simultaneous (e.g., Cook v. Lewis)
distinct and successive (e.g., Caneric)
Plurality of Established Causes
A general principle in both systems is that a defendant need not have caused the entire injury in order to be liable for it.
There are three ways of dividing liability in cases of cumulative causes:
1. solidarity (civil law) / joint and several liability (common law)
2. “apportionment” or “division” of liability
3. holding only the second defendant (or rather, the second event) liable.
solidarity (civil law) / joint and several liability (common law):
In this scheme, the plaintiff can recover damages from either defendant.
This maximizes the plaintiff’s chances of actually getting her money.
The defendant who pays can then demand reimbursement (usually 50%) from the other defendant.
In civil law, solidarity is found in (a.1526).
Solidarity applies in principle to distinct and successive contributive faults that cause one single injury.
It also applies to joint faults that cause one single injury.
Defendants may be assigned different shares of the solidary liability on the basis of the relative seriousness of their faults (a.1478).
Common law has basically the same rules, derived from statute.
Deguire Avenue Ltd. v. Adler,  B.R. 101. (CB2p158)
Adler was the manager of Deguire’s apartment building, although he posed as owner. Painters, personally employed by Adler, came to paint a vacant apartment. In the course of their work, they disconnected the oven from its gas supply, and turned off the supply in the basement. They did not reconnect the oven when they left. A few weeks later, Deguire’s janitors, working on the gas supply in the basement, accidentally turned on the gas for the vacant apartment. A few hours later, the same janitors went into the vacant apartment to show it to prospective tenants. They noticed it was filled up with gas, and tried to dissipate it. About 15 minutes later, the gas exploded (what sparked the explosion is unknown).
Was the fault of the painters too distant to be considered a cause of the explosion?
The fault of the painters was “continuous” with the fault of the janitors. These were distinct and successive contributive faults. Both Adler (as the painters’ employer) and Deguire (as the janitors’ employer) could be held solidarily liable. (The immediate cause of the explosion was ignored by the court because of a lack of evidence.)
Owen J, dissenting, thought that the painters’ act was not determinative in causing the injury—thus he held that there was no causation.
Caneric Properties Inc. v. Allstate,  R.R.A. 296. (CB2p166)
Caneric owned a building in Old Montreal which was slated for demolition. During the winter, Caneric did not heat the building or turn off the water. A pipe burst, leaking into the basement of the neighbouring hardware store. The hardware store owner asked