460 P.3d 1201
Cal.2020Background
- Montrose operated a DDT manufacturing facility in Torrance (1947–1982), was sued for long‑term environmental contamination, entered consent decrees, and has paid/expects well over $100 million in cleanup costs.
- Montrose purchased primary and multiple layers of excess comprehensive general liability insurance for policy years 1961–1985; the parties agree primary coverage is exhausted.
- Each excess policy conditions coverage on exhaustion of “underlying insurance” and contains varying “other insurance” language; some policies list same‑period underlying policies or state a same‑period dollar attachment point.
- Montrose sought a declaration permitting vertical exhaustion (may tap any excess policy once its directly underlying same‑period excess is exhausted); insurers argued for horizontal exhaustion (must exhaust all lower‑attachment excess policies across every policy year implicated by the continuous injury).
- Trial court and Court of Appeal adopted horizontal exhaustion; the Supreme Court granted review to decide whether vertical or horizontal exhaustion governs in a continuous‑injury, multiyear context.
Issues
| Issue | Plaintiff's Argument (Montrose) | Defendant's Argument (Insurers) | Held |
|---|---|---|---|
| Proper exhaustion rule for excess policies in continuous (long‑tail) injuries | Vertical exhaustion: insured may access any excess policy once directly underlying same‑period excess is exhausted | Horizontal exhaustion: insured must exhaust all lower‑attachment excess policies across every policy period where injury occurred before accessing higher excess | Vertical exhaustion applies unless parties contract otherwise; insured may access an excess policy once the directly underlying same‑period excess is exhausted |
| Meaning/effect of “other insurance” clauses in excess policies | They do not clearly require horizontal exhaustion; historically govern allocation among concurrent insurers, not sequencing across successive policies | Clauses require exhaustion of all available lower‑attachment insurance across periods (i.e., horizontal exhaustion) | “Other insurance” clauses do not clearly mandate horizontal exhaustion; read with attachment‑point language and schedules, they naturally refer to directly underlying same‑period insurance |
| Role of insureds’ reasonable expectations and policy language ambiguity | Ambiguities should protect insured’s objectively reasonable expectation to access coverage at stated attachment points | Insurers: all‑sums stacking supports a horizontal rule to avoid segmenting continuous loss | Reasonable expectations and practical administrability favor vertical exhaustion; ambiguities resolved for insured |
| Whether Supreme Court should decide Travelers’ separate defenses (choice of law; actual exhaustion requirement) | Montrose did not ask for resolution of Travelers’ distinct arguments here | Travelers argued their policies require actual exhaustion and that non‑California law applies | Court declined to decide those separate Travelers issues; left for Court of Appeal on remand |
Key Cases Cited
- Montrose Chemical Corp. v. Admiral Ins. Co., 10 Cal.4th 645 (1995) (continuous‑injury trigger: insurer on risk when injury first manifests remains liable for ensuing damage)
- Aerojet‑General Corp. v. Transport Indemnity Co., 17 Cal.4th 38 (1997) (all‑sums rule: if some harm occurs during a policy period, that policy can be liable for the full loss up to its limit)
- State of California v. Continental Ins. Co., 55 Cal.4th 186 (2012) (adopts all‑sums‑with‑stacking for long‑tail injuries, allowing insured immediate access to triggered policies)
- Dart Industries, Inc. v. Commercial Union Ins. Co., 28 Cal.4th 1059 (2002) (explains "other insurance" clauses allocate among insurers but do not defeat an insurer’s contractual obligation to the insured)
- Community Redevelopment Agency v. Aetna Casualty & Surety Co., 50 Cal.App.4th 329 (1996) (applied horizontal exhaustion in a distinct contribution/defense context)