Ministry of the
Solicitor General

Hazard Identification Report 2019 - Section E - Health Hazards


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Hazard Identification and Risk Assessment Program

Hazard Identification Report 2019
Section E: Health Hazards

Office of the Fire Marshal & Emergency Management


The Hazard Report contains information profiles for hazards, including a high-level overview of possible consequences. It is divided into 10 parts; an introduction and 9 sub-sections labelled A-I as follows:

  1. Agriculture and Food
  2. Environmental
  3. Extraterrestrial
  4. Hazardous Materials
  5. Health
  6. Public Safety
  7. Structural
  8. Supply and Distribution
  9. Transportation


Public Health Hazards: Hazards relating to public health.

Water Quality Emergency

Go to next sub-section: Infectious Disease Outbreak


A widespread or severe incident of contamination that presents a danger to or otherwise endangers the general health and well-being of the public.[1]


The quality of water is essential to maintaining good public health. Drinking water supply may be negatively affected by natural, agricultural, public safety incidents or other hazards.[2]

When people are exposed to contaminants in high concentrations a person can experience harmful effects.[3] The quantity of contaminate in water and the amount of water ingested determine the severity of these effects. Ingestion is the most common route of exposure, though some toxins can be absorbed through the skin or by inhalation while taking a shower.[4] Common symptoms include gastrointestinal pain, gastrointestinal infection, and diarrhoea. Delays in the onset of symptoms may result in continued exposure as the outbreak remains undetected

Depending on the pathogens or contaminants, it may take a long time, sometimes months, years or even centuries for the quality to return to safe levels.

Across Canada, strict practices are in place govern land use in order to protect source water, and mitigate contamination risk. Similarly stringent practices are used to ensure water treatment. Ground and lake water is treated before it becomes drinking water in order to remove pathogens and other contaminants.

Examples of protective measures include source water protection legislation, treatment facilities, treated water storage (elevated and in-ground), distribution systems, technological controls and monitoring, trained operators, and quality monitoring by sampling and analysis. In order for a water quality emergency to occur, there would have to be a failure in one or more of these components.[5]

The maintenance of water systems requires long-term capital investment and asset management planning that are among the most costly and complex tasks conducted by local water service providers.

In 2017, 99.8% of more than 518,000 test results from municipal residential drinking water systems met Ontario’s strict drinking water quality standards. While over 80% of Ontarians receive their drinking water from municipal residential drinking water systems, there are also sources of water in Ontario that are non-municipal or private.

Since the Walkerton Crisis in 2000, the approach to water quality assurance has dramatically improved in Ontario, now consisting of a multi-barrier approach of strong legislation, stringent health-based standards, regular and reliable testing, highly trained operators, regular inspections and a source water protection program. In 2007 the Ontario government announced completion of all 121 findings of the Walkerton enquiry.[6],[7]

Spatial Scale, Timing and Warning

Spatial Scale: varies, although it may impact the entire water source for a community/region.

Timing: no seasonal or diurnal variation.

Warning: warning period varies depending on circumstances.

Potential Impacts

A water quality emergency may result in:

  • Illness or death. May strain the health system and response resources.
  • Reputational Damage.
  • The need for emergency provision of essential needs, including food.
  • Long-term population health monitoring.
  • The need for remediation. Possible impact on Critical Infrastructure.

Secondary Hazards

Potential secondary hazards may include:

  • Human illnesses or outbreaks

Past incidents

Walkerton, 2000: An outbreak of waterborne gastroenteritis was the result of a poor management of the water treatment facility and improper testing of the water supply in Walkerton, ON. A heavy rainstorm washed cattle manure from agricultural lands into a town well, contaminating the water with the E. coli and Campylobacter jejuni bacteria. This sickened more than two thousand people and resulted in six deaths.[8] The crisis also damaged public confidence in Ontario’s water quality control systems.

Provincial Risk Statement

Water quality emergencies are usually isolated to the area serviced by the local utility that distributes water.

Risks to water quality include challenges with maintenance of aging infrastructure, particularly underground assets that are more costly and difficult to access, and especially in remote settings. Pressures also include population growth, rapid development, and invasive species. The changing climate is compounding the situation, with droughts and floods, extreme storms and declining ice cover causing shoreline erosion, warmer water and harmful algae. Litter, plastics and micro-plastics found in the Great Lakes and inland waterways are a growing problem.[9]

Human impacts

The influx of people seeking medical attention has the potential to place significant strain on the public health and health care system. A large number of residents from the affected area may seek medical attention whether or not they have begun to show symptoms. Areas with a high population density that are reliant on one or very few water sources are particularly susceptible. Many remote communities are also at risk since the delivery of alternative sources of water may be time-consuming and expensive.

Social Impacts

Disruption of an area’s water distribution can severely strain social support networks and structures.

Property Damage

The property and infrastructure of Ontario is unlikely to be harmed by a water quality emergency. However, both water treatment plants and distribution systems may require full assessments to ensure treatment processes are back to normal performance levels before they are able to serve the public again.

Critical Infrastructure Disruptions

All critical infrastructure are reliant on staff resources, who are dependent on the distribution of clean water. Perceived or actual human health effects are potentially disruptive to all critical infrastructure. Clean water is also critical to the safe delivery of these services, including healthcare.

Environmental Damage

The environment can be vulnerable to a water quality emergency. The level of environmental damage depends on where in the system the water quality declined. If the decline occurred in the source water (e.g. a lake or river) then aquatic organisms and other species that rely on that resource may be harmed.


A significant decrease in drinking water quality or quantity could result in a significant economic loss to the affected community including business interruptions, a decline in tourism and investment, reduced property values and compensation payments to victims and their families.

Infectious Disease Outbreak

Go to previous hazard: Water Quality Emergency

Go to next hazard: Substance Use and Overdose


An infectious disease outbreak is defined generally as a widespread incident of disease or other situation that presents a danger to the general health and well-being of the human population.[10]

Infectious diseases are caused by pathogenic microorganisms, such as bacteria, viruses, parasites or fungi. These diseases can be acquired from another person, through fluid exchange or exposure to vectors, or from the environment.

Infectious diseases can become an epidemic or pandemic:[11]

Epidemic: An outbreak of infection that spreads rapidly and affects many individuals in a given area or population at the same time.

Pandemic: An epidemic occurring worldwide, crossing international boundaries and usually affecting a large number of people.


Infectious disease outbreaks can arise from different pathogens. Some of these include viruses, bacterium, parasites, fungi and protozoa, which are vital and usually innocuous members of the ecosystem. While the vast majority of them are harmless or even beneficial to human health, a small minority are dangerous to humans. The severity of the symptoms depends on factors such as the source of the illness and the health and age of the host.

Types of diseases include:

  • Airborne/Droplet: Refers to situations where residue from evaporated droplets or dust particles containing microorganisms can remain suspended in air for long periods of time.[12]
  • Vector Borne: Living organisms can transmit infectious diseases between humans or from animals to humans.[13]
  • Blood borne: Blood borne pathogens, infectious microorganisms, are found in human blood that can lead to disease in humans[14].
  • Zoonotic: Diseases that can be transmitted from animals to humans by either contact with the animals or through vectors that carry zoonotic pathogens to from animals to humans.
  • Enteric Infectious enteric disease refers to gastrointestinal illnesses that result from ingesting micro-organisms that may be traced back to food, water, animals or an infected person. Some examples are Salmonella, E. coli, Listeria and Giardia.

There are many factors that can cause infectious diseases, such as the evolution of micro-organisms (including antibiotic-resistant strains), the alteration of natural habitats, the increasing frequency and the decreasing duration of global travel.[15]

Infectious disease outbreaks and their severity are influenced heavily by human behaviour, even though they are naturally occurring.[16] There are several ways an infectious disease outbreak can be introduced and spread:[17]

  • Direct contact
  • Indirect contact
  • Droplet contact
  • Airborne transmission
  • Vector-borne transmission

Given that pathogens can easily cross-jurisdictional boundaries, from a known or unknown agent of disease, efforts to mitigate and respond to infectious disease should occur at all levels and across borders, to ensure appropriate collaboration and planning takes place and to ensure that communities are prepared to effectively contain the spread of an illness and limit its impact.[18]

The Ontario Public Health Standards (OPHS) are published by the Ministry of Health and Long-Term Care under the authority of the Health Protection and Promotion Act (HPPA) to specify the mandatory health programs and services provided by boards of health.[19] The Infectious disease protocol is to provide boards of health with direction with respect to the prevention and management of infectious diseases of public health importance.

Public Health Ontario’s Communicable Diseases, Emergency Preparedness and Response department provides evidence-based scientific and technical advice to local, provincial and federal partners in government, public health and healthcare.

Spatial Scale, Timing and Warning

Spatial Scale: Varies, although impacts are usually across an entire community/region.

Timing: There are seasons where certain diseases are more likely. For example, peak influenza season is typically from November through to March.

Warning: The amount of warning can vary significantly, but there is often a period of weeks to months between the identification of the initial cases and greater transmission, depending on the location of initial cases and mode of spread within the environment. Monitoring and forecasting by experts can assist with predictions.

Potential Impacts

An infectious disease outbreak may result in:

  • Illness or death. May strain the health system and response resources.
  • Enhanced surveillance and monitoring activities.
  • Possible need for mass immunization or treatments.
  • Reputational Damage.
  • Long-term population health monitoring.
  • Worker shortages and business continuity issues.
  • The need for site or area access restrictions.
  • The need for case and contact management, such as isolation and quarantine.
  • The need for financial assistance.
  • The need for site or area access restrictions.

Secondary Hazards

Potential secondary hazards may include:

  • Supply and disruption hazards
  • Medical drug, blood product or supplies shortage

Provincial Risk Statement

There is an apparent increase in many infectious diseases, including some newly-circulating ones.[20] Improvements in prevention, early detection, control and treatment are also becoming more effective at reducing the number of people infected.[21]

Dense populations, especially with a growing and mobile population and global reach, are thus at high risk for the introduction of diseases into the population. Changes in global temperature, precipitation, and extreme events could increase the geographic range of vector-borne diseases.[22]

As more antimicrobial drugs become ineffective and fail to treat a growing number of infections, those infections persist and increase the risk of disease, poor health and death.[23]

To address these emerging and other risks, emergency planners can integrate understandings of social determinants of health into their program activities. Examples of key sources of expertise include local and regional health partners and social service organizations, Social Services Administration Boards, local Indigenous communities and specialized social support and health groups.

Human impacts

The symptoms of infectious disease can be serious and in some cases life-threatening. The specific impact depends on a number of factors including vulnerability, which varies for each type of illness, as well as environmental, social, economic and other conditions.

There are numerous potential mental health impacts have been associated with past infectious disease emergencies, including stress or anxiety following isolation or quarantine orders/recommendations.

Social Impacts

Potential social effects are varied, and include community financial loss or employment loss due to need to quarantine or isolate, stigma, disruption in the activities of daily living.

Property Damage

Property damage is not likely from an infectious disease outbreak.

Critical Infrastructure Disruptions

While some critical infrastructure services may suffer due to large numbers of workers being sick or caring for others, the probability is low and dependent on the severity of the emergency.

Environmental Damage

Environmental damage is not a likely impact of an infectious disease outbreak. However unsafe disposal of infected materials could be of concern.


The business and finances of Ontario are vulnerable to this hazard. The severity of the business and financial interruption depends on the transmission mode and the virulence of the illness. If large numbers of the workforce became ill or if travel restrictions are used to control spread, significant business and financial interruptions could occur.

Substance Use & Overdose

Go to previous hazard: Infectious Disease Outbreak (Epidemic, Pandemic)


A public health emergency resulting from problematic or harmful use of prescription drugs or other controlled substances.


Harmful substance use can occur when an individual overindulges or is dependent on an addictive substance, especially alcohol or drugs. When individuals consume a substance in amounts or with methods which are harmful to themselves or others this is a form of a substance-related disorder.

Certain prescription drugs, like opioids, sedative-hypnotics and stimulants, are associated with serious harms like addiction, overdose and death.[24] While common opioids such as oxycodone, hydromorphone and fentanyl can be an effective part of pain management for some medically supervised patients, opioid-related harms such as present a significant challenge for public health.[25][26]

These drugs can have a devastating impact on individuals, their families and their communities. They can also place a significant burden on public health, social services and public safety systems. Because of these factors, such substances have become a leading public health and safety concern.[27]

The pressures placed on the healthcare system from substance abuse and addictions can result in severe stress on the normal delivery of services, if not managed properly.[28] Additionally, the coping capacity for such trends for communities across Ontario varies greatly depending on local social, economic, cultural, and spiritual factors, and other pressures.

Public Health Ontario provides support to the Ministry of Health and Long-Term Care’s comprehensive opioid strategy, and to local public health units responding to opioid-related harms. This is important in assembling, analyzing and visualizing data on opioid-related morbidity and mortality in Ontario, and providing scientific expertise and consultation.

The opioid emergency task force, convened in 2017, includes front-line harm reduction workers, emergency responders, mental health and addiction professionals, public health experts, other provincial ministries and municipal representatives, health-care groups and people who live with addiction.[29]

Spatial Scale, Timing and Warning

Spatial Scale: Varies considerably, from hyper-local to province or country-wide crises. Such events often have no definitive or clear start or end.

Timing: No seasonal or diurnal variation.

Warning: warning period varies depending on circumstances; although, such emergencies can result from systemic social issues, or supply chain trends. In some circumstances, experts tracking these related patterns and/or early warning systems can provide insight.

Potential Impacts

A large number of overdoses or overdoses in a geographic area may be an emergency and may result in:

  • Illness or death. May strain the health system and response resources.
  • The need for increased public safety or policing measures.
  • Enhanced surveillance and monitoring activities.
  • Need for specific drug treatments, urgent care, or specialized health services.

Secondary Hazards

Pressure created by ‘substance use and overdose’ emergencies may create a Geopolitical hazard affecting Ontario.

Past Incidents

As ‘substance use and overdose’ crises have no definitive or clear start or end date or time, it is challenging to provide a definitive list of past events.The information below includes an overview of some recent significant statistics related to this hazard.

  • According to data collected by the Chief Coroner of Ontario, in 2017 there were 1,261 recorded opioid-related deaths. This is a 45% increase from the number of deaths in 2016.
  • More than 7,000 Ontarians died of an opioid overdose between 2007 and 2017, the majority unintentionally.[30]
  • The rate of Opioid-related Emergency Department visits in August 2017 was 6.8 per 100,000 for Ontario. This is the highest rate ever recorded.[31]

Provincial Risk Statement

One of the most significant challenges to addressing this threat has been the lack of consistent data and methodology for identification of hospital visits related to opioid toxicity. In recent years, Ontario has significantly reduced this gap.

In spite of existing efforts, risk reduction programs and initiatives need to ensure that the interventions, models of care, and policies being developed and implemented on an ongoing basis are examined for their effectiveness and scalability, across jurisdictions, and for key populations.[32]

Human impacts

The population of Ontario, like any other human population, is vulnerable to substance use and overdose emergencies. However, the effects are usually limited or localized in scale.

Social Impacts

Where community networks and support structures are already weakened by systemic social issues, it is more likely that community-wide impacts will result from harmful substance use and overdose, leading to emergency conditions.

Property Damage

Property damage is not likely.

Critical Infrastructure Disruptions

Critical infrastructure disruption is not likely, but stress on social support, health and other such initiatives is a distinct possibility. The extent of disruption depends on the level of capacity of local and provincial systems to cope with specific incidents.

Environmental Damage

Environmental damage is not likely.


Economic damage is likely only in situations where the local or regional community or social network has been disrupted, causing knock-on effects to the local economy.

End Notes

[1] Ministry of Health and Long Term Care, 2018. correspondence [via email], October 2018

[2] Government of Ontario, 2018. Drinking Water. Acessed December 2018.

[3] Canadian Environmental Health Atlas (2018)

[4] Government of Ontario, Drinking Water, 2018.

[5] Chief Drinking Water Inspector, Annual Report 2016-17.

[6] Ontario Newsroom, 2007.

[7] The Walkerton Enquiry, 2002. Official website of the public inquiry. Accessed October 2018.

[8] Ministry of the Environment, Conservation and Parks, 2017. 2016-2017 Chief Drinking Water Inspector Annual Report.

[9] Ministry of the Environment, Conservation and Parks, 2018. Minister’s Annual Report on Drinking Water 2018.

[10] Ministry of Health and Long Term Care, 2018. [via email], May 2018

[11] Health Canada, 2017. Glossary: Canadian Pandemic Influenza Preparedness: Planning Guidance for the Health Sector.

[12] Mount Saini Hospital, Department of Microbiology (2017)

[13] World Health Organization, 2018.

[14] Centres for Disease Control and Prevention, 2018

[15] Public Health Ontario, 2018. Infectious Diseases.

[16] World Bank, 2017. Backgrounder paper - Pandemic Risk.
Accessed February 2018.

[17] Background paper on Pandemic Risk, World Bank, 2014.

[18] Ministry of Health and Long Term Care, 2017. Emergency Planning and preparedness - Influenza Pandemic.

[19] Ministry of Health and Long Term Care, 2018. Ontario Public Health Standards: Requirements for Programs, Services, and Accountability (Standards).

[20] World Health Organization, 2015.

[21] Smith et al, 2014. Global rise in human infectious disease outbreaks. Journal of the Royal Society.

[22] United States Environmental Protection Agency, 2017.

[23] Public Health Ontario, 2018.

[24] Canadian Centre for Drug Use and Addiction, 2013. First, Do No Harm: Responding to Canada’s Prescription Drug Crisis.

[25] World Health Organization, 2014. World Drug Report,

[26] Centre for Addiction and Mental Health, 2012. Accessed April 2018.

[27] Government of Canada, 2017. Government of Canada Actions on Opioids: 2016 and 2017. Accessed November 2017.

[28] Canadian Centre for Substance Use and Addiction, 2014. Canadian Substance Use Costs and Harms 2007-2014. Accessed April 2018.

[29]Ministry of Health and long Term Care, 2018. Opioids - Opioid Emergency Task Force Membership List.

[30] National Ambulatory Care Reporting System (NACRS), CIHI

[31] Ministry of Health and long Term Care, Opioid-related morbidity and mortality in Ontario, 2018.

[32] Backgrounder: Review of Supervised Consumption Services and Overdose Prevention Sites - Key Findings, 2018.