Decision Nº ReleasedDecisionsWithSummaryAdded from Workplace Safety and Insurance Appeals Tribunal of Ontario, 19-07-2023

JudgeG. Dee: Vice-Chair C. Sacco: Member Representative of Employers M. Tzaferis: Member Representative of Workers
Judgment Date19 July 2023
Neutral Citation2023 ONWSIAT 1082
Judgement NumberReleasedDecisionsWithSummaryAdded
Hearing Date23 November 2021
IssuerWorkplace Safety and Insurance Appeals Tribunal of Ontario
WSIAT Decision - 1741 21


Decision No. 1741/21


G.Dee (FT) - C.Sacco - M.Tzaferis

  • Causation (thin skull doctrine)
  • Post-traumatic stress disorder
  • Statutory interpretation (principles of)
  • Preexisting condition (psychological condition)
  • Board Directives and Guidelines (stress, mental) (traumatic event)

The worker sought entitlement for a mental stress condition, in the form of post-traumatic stress disorder (PTSD). The claimed date of onset of the worker's mental stress condition was October 16, 2018. On this date, a child started to behave inappropriately in the worker's classroom, including having physical outbursts. The worker was punched and kicked by the child, and stabbed in the leg with a pencil. Entitlement under the Board's policy on Traumatic Mental Stress (TMS) was denied on the basis that the incident of October 16, 2018 was not objectively traumatic.

The appeal was allowed.

The Panel found that the incident that the worker was involved in on October 16, 2018 arose out of and in the course of the worker's employment and worsened her pre-existing psychological difficulties. OPM Document No. 15-03-02 requires that an event that precipitates an injury be "objectively traumatic" and sets out examples. Consistent with a number of other Tribunal decisions that have considered entitlement to TMS, the Panel found that injuring events are not required to be similar in nature to the events listed in OPM Document No. 15-03-02, in order to be considered "objectively traumatic".

The Panel found that the incident that the worker experienced was objectively traumatic, despite the fact that the incident was not similar in nature to the examples provided in OPM Document No. 15-03-02. There was an element of concern by the worker for her own personal safety, but also a significant concern for the children under her care, which the worker was responsible for protecting. The incident was followed by the worker's immediate breakdown and very prompt health care being received and acceptance by the health care providers that the incident caused the breakdown. These circumstances demonstrated the objectively traumatic nature of the event that the worker experienced. The worker was diagnosed with PTSD, which met the diagnostic requirements set out in OPM Document No. 15-03-02.

The Panel preferred the definition of what it means for an incident to be considered "objectively traumatic" in line with prior Tribunal decisions that require an event to be considered traumatic by a neutral observer and not just by the worker (see Decision No. 509/07). Using the language of Board policy and Decision No. 2185/11, it is a requirement for entitlement to traumatic mental stress that an event "is generally accepted as being traumatic." There is, however, no requirement in section 13 of the WSIA or in OPM Document No. 15-03-02 that the mental stress must be analogous to the types of examples of traumatic mental stress incidents found in OPM Document No. 15-03-02.

Given that the worker's job was to maintain a safe learning environment for the children under her care, the Panel found that the events of October 16, 2018 represented a very significant concern that potentially endangered the children under her care, and for which she potentially stood to be held responsible. This qualified as being objectively traumatic, even aside from the threat the events posed to her personal security. The Panel concluded that the worker had entitlement for a mental stress injury under section 13 of the WSIA and the Board's policy on TMS.

28 Pages


Act Citation

  • WSIA

Other Case Reference

  • [w3523s]
  • BOARD DIRECTIVES AND GUIDELINES: Operational Policy Manual, Document No. 15-03-02
  • CASES CONSIDERED: Rizzo and Rizzo Shoes Ltd. (1997), 1998 CanLII 837 (SCC), 154 D.L.R. (4th) 193 (SCC) refd to; Nova Scotia (Workers’ Compensation Board) v. Martin, [2003] 2 S.C.R. 504 (S.C.C.) refd to
  • TRIBUNAL DECISIONS CONSIDERED: Decision No. 1362/06I, 2006 ONWSIAT 2253 refd to; Decision No. 509/07, 2007 ONWSIAT 807 refd to; Decision No. 1368/22, 2022 ONWSIAT 2085 refd to; Decision No. 133/22, 2023 ONWSIAT 579 refd to; Decision No. 483/11I, 2011 ONWSIAT 1231 refd to; Decision No. 483/11, 2011 ONWSIAT 2257 refd to; Decision No. 2185/11, 2012 ONWSIAT 1433 refd to; Decision No. 505/21, 2022 ONWSIAT 475 refd to; Decision No. 921/21, 2021 ONWSIAT 1661 refd to; Decision No. 1529/21, 2023 ONWSIAT 490 refd to

Style of Cause:

Neutral Citation:

2023 ONWSIAT 1082


DECISION NO. 1741/21

BEFORE: G. Dee: Vice-Chair

C. Sacco: Member Representative of Employers

M. Tzaferis: Member Representative of Workers

HEARING: November 23, 2021 at Toronto Oral by Teleconference

Post-hearing activity complete January 6, 2023

DATE OF DECISION: July 19, 2023


DECISION(S) UNDER APPEAL: WSIB Appeals Resolution Officer decisions dated

February 28, 2020 and August 4, 2020


For the worker: E. DePoe, Paralegal

For the employer: S. Postill, Lawyer

Interpreter: N/A

Workplace Safety and Insurance Tribunal d’appel de la sécurité professionnelle Appeals Tribunal et de l’assurance contre les accidents du travail

505 University Avenue 7th Floor 505, avenue University, 7e étage

Toronto ON M5G 2P2 Toronto ON M5G 2P2


(i) Issue

[1] The worker seeks entitlement for a mental stress condition. The claimed date of onset of the worker’s mental stress condition is October 16, 2018.

[2] Following the denial of benefits for mental stress by the Workplace Safety and Insurance Board (WSIB or the Board) the worker asserted that the WSIB’s policies on entitlement for mental stress contravene the requirements of the Canadian Charter of Rights and Freedoms and the Ontario Human Rights Code. The WSIB has issued a final decision denying that its policies contravene the Charter or Human Rights Code.

[3] The hearing before the Appeals Tribunal has been bifurcated. The consideration of whether the WSIB’s policies are consistent with the Charter or Human Rights Code will not be addressed unless the worker’s appeal pursuant to the WSIB’s existing policies is unsuccessful. This is being done in accordance with the provisions of the Tribunal’s Practice Direction: Procedure When Rising a Human Rights or Charter Question.

(ii) Background

[4] The worker was an educational assistant in a primary school.

[5] Prior to October 16, 2018 the worker was receiving counselling for psychological difficulties and had been prescribed an anti-depressant medication.

[6] Prior to October 16, 2018 the worker had also required workplace accommodatio...

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