Managing Environmental Health, Hygiene, and Sanitation During Disasters

When a disaster strikes – whether it’s an earthquake, flood, cyclone, or conflict – the immediate threat is obvious: collapsed buildings, rising waters, displaced families. But a second, less visible crisis almost always follows. The breakdown of water systems, the failure of sanitation infrastructure, and the collapse of basic hygiene conditions create a dangerous breeding ground for disease outbreaks. In many past disasters, more people have died from preventable communicable diseases in the aftermath than from the disaster event itself. Understanding how environmental health, hygiene, and sanitation intersect during emergencies is essential for anyone working in – or studying – disaster management.

Why sanitation collapses during disasters 🔗

Most disasters damage or completely destroy the infrastructure that communities depend on for clean water and waste disposal. Piped water systems break, sewage lines rupture, latrines flood, and solid waste management systems stop functioning. When this happens, affected populations are forced to rely on contaminated water sources and open defecation, both of which dramatically raise the risk of disease.

The problem intensifies when large numbers of displaced people are moved into temporary shelters and relief camps. Overcrowding, combined with inadequate hygiene and poor water supplies, increases the incidence of diarrhoea, malaria, respiratory infections, and measles. These are not theoretical risks – diarrhoeal diseases, measles, acute respiratory infections, and malaria together account for 60-95% of reported deaths among displaced populations after crises.

Several factors determine just how severe the sanitation crisis becomes after a disaster. These include the pre-existing state of infrastructure, population density in camps, the extent of damage to utilities, contamination of water and food sources, and the disruption of ongoing public health programmes such as immunisation and vector control.

The impact of poor sanitation on public health in disasters 🔗

When sanitation fails, disease transmission accelerates through well-understood pathways. The faecal-oral route is the primary concern – human waste contaminates water sources, which are then used for drinking and cooking. Without functioning toilets and handwashing facilities, pathogens spread rapidly through communities.

Waterborne and water-related diseases 🔗

The most immediate health threats from poor sanitation during disasters are waterborne diseases. Cholera, typhoid fever, hepatitis A, and various forms of dysentery can spread explosively when untreated sewage enters drinking water systems. According to the World Health Organization, the deterioration of environmental conditions during emergencies often results in a steep rise in WASH-related diarrhoeal disease, depending on the vulnerability of the affected population and the capacity of local systems.

Beyond waterborne diseases, stagnant water from flooding and poor drainage creates ideal breeding conditions for mosquitoes, leading to spikes in vector-borne diseases like malaria and dengue. Flies breeding in accumulated solid waste can also transmit diseases like trachoma.

Vulnerable populations at greatest risk 🔗

Children under five, pregnant women, elderly individuals, and people with compromised immune systems are disproportionately affected by sanitation failures during disasters. Malnutrition – which is common in disaster-affected populations – weakens the body’s ability to fight off infections, creating a dangerous cycle where poor nutrition makes people more susceptible to disease, and disease further worsens nutritional status.

The environmental health risks are compounded in regions with pre-existing infrastructure deficits, particularly in sub-Saharan Africa and parts of South Asia, where baseline access to safe water and sanitation is already limited.

Key measures to ensure safe water and sanitation 🔗

Effective disaster response requires the rapid restoration – or establishment – of basic water, sanitation, and hygiene (WASH) services. International frameworks, particularly the Sphere Humanitarian Standards, provide detailed guidelines that humanitarian agencies use as benchmarks during emergency response.

Providing safe drinking water 🔗

Safe water provision is the single most critical intervention in the early stages of a disaster. The UNHCR recommends that each affected person receive a minimum of 15-20 litres of clean water per day for drinking, cooking, and basic personal hygiene. Importantly, having adequate quantities of reasonably clean water is considered more beneficial than having small amounts of highly purified water.

In practice, emergency water supply involves several approaches. These include distributing water purification tablets or chlorine for household treatment, setting up temporary water treatment units, trucking in clean water, and identifying and protecting uncontaminated natural sources. Water quality testing must be ongoing, and water distribution points should be accessible to all camp residents, including those with mobility limitations.

Emergency sanitation and excreta disposal 🔗

Latrine construction is a first priority and should begin during the acute phase of an emergency. The international standard calls for one latrine for every 20 people, and these should be positioned at a safe distance from water sources to prevent contamination. In the earliest hours, when construction is not yet possible, simply designating defecation areas that are separated from water sources is a critical interim measure.

Beyond latrines, solid waste management systems must be quickly established. Uncollected rubbish attracts disease-carrying vectors like rats, flies, and mosquitoes. Medical waste from emergency health facilities requires special handling and disposal procedures to prevent further contamination.

Hygiene promotion and education 🔗

Providing infrastructure alone is not sufficient. Simply providing water and sanitation facilities will not ensure their optimal use unless affected populations understand how to use them correctly. Hygiene promotion programmes must run alongside infrastructure deployment.

The key behaviours that hygiene campaigns target include handwashing with soap after using toilets and before handling food, safe water storage practices at the household level, proper food preparation and handling, and safe disposal of children’s faeces. These messages are most effective when delivered through community health workers and local leaders who understand the cultural context of the affected population.

Vector control 🔗

Controlling disease-carrying vectors is another essential environmental health intervention during disasters. Mosquito breeding sites need to be eliminated through proper drainage, and insecticide-treated nets should be distributed in malaria-endemic areas. Fly control around latrines and food distribution areas, along with rodent management through proper waste disposal, are equally important components of a comprehensive WASH response.

International standards guiding disaster WASH response 🔗

The Sphere Handbook is the most widely recognised reference for humanitarian response quality. Published by the Sphere Association, it sets out minimum standards across four key areas: WASH, food security and nutrition, shelter, and health. On the WASH side, it provides specific benchmarks for water quantity and quality, sanitation facilities ratios, vector control, solid waste management, and drainage.

The WHO also works with member states across the full disaster management cycle – from prevention measures and early warning systems to emergency response and long-term recovery of water and sanitation infrastructure. WHO’s approach emphasises that environmental health risks must be addressed through preparedness planning long before a disaster occurs, not just in the response phase.

The UNHCR provides additional guidance tailored to refugee and displacement settings, emphasising the importance of transitioning from emergency-phase interventions to more sustainable, longer-term WASH systems once populations stabilise.

Real-world examples of sanitation failures 🔗

Some of the most devastating post-disaster health crises in recent history have been directly caused by failures in water, sanitation, and hygiene management. Examining these cases offers important lessons.

The Haiti cholera outbreak (2010) 🔗

The most widely cited example of a sanitation-driven disaster health crisis is the cholera epidemic that struck Haiti in October 2010, nine months after a devastating 7.0-magnitude earthquake that killed over 200,000 people and displaced more than a million.

Haiti’s WASH infrastructure was severely deficient even before the earthquake. According to the CDC, only 63% of Haiti’s population had access to an improved drinking water source in 2008, just 12% received piped treated water, and only 17% had access to adequate sanitation. The earthquake further devastated what little infrastructure existed.

The cholera outbreak was eventually traced to a UN peacekeeping camp near Mirebalais that had deficient sanitation, with sewage from the camp being discharged into a tributary of the Artibonite River. Villagers downstream used water from this same river for drinking and cooking. The disease spread rapidly across the country – within 29 days, all ten of Haiti’s administrative departments had confirmed cases.

The scale of the epidemic was staggering. According to the CDC’s Office of Readiness and Response, the outbreak resulted in more than 820,000 cases and nearly 10,000 deaths, making it the worst cholera epidemic in recent history. Haiti had not experienced a single case of cholera for over a century before this outbreak – the population had no prior immunity, which contributed to the severity.

The Haiti case demonstrates several critical lessons. First, pre-existing sanitation deficits make populations extremely vulnerable when disaster strikes. Second, improper waste management by any actor – including international aid organisations – can trigger catastrophic health consequences. Third, the absence of rapid WASH interventions allows preventable diseases to spread at epidemic scale.

Hurricane Katrina and environmental contamination (2005) 🔗

When Hurricane Katrina struck the US Gulf Coast in 2005, floodwaters mixed with raw sewage, industrial chemicals, and household waste, creating severe environmental health hazards. The flooding overwhelmed municipal water treatment and sewage systems in New Orleans and surrounding areas. Displaced populations in temporary shelters faced sanitation challenges, and the disaster highlighted the need for integrated environmental health planning that extends well beyond the emergency phase.

Typhoon Haiyan and sanitation recovery (2013) 🔗

When Typhoon Haiyan devastated the Philippines in 2013, the sanitation response included the deployment of eco-sanitation toilets as a practical and environmentally sustainable solution. This approach demonstrated that integrating local knowledge and culturally appropriate practices into sanitation responses leads to better community acceptance and use of facilities – a lesson now incorporated into international WASH guidelines.

Building long-term resilience in environmental health 🔗

While emergency WASH response saves lives in the short term, lasting progress requires investment in resilient infrastructure that can withstand disasters. This means building water treatment facilities and sewage systems that are designed to function – or be rapidly repaired – after seismic events, floods, or storms.

Community-based preparedness is equally important. Populations in disaster-prone areas need ongoing hygiene education, local water quality monitoring capacity, and contingency plans for sanitation during emergencies. Public health surveillance systems must be able to detect disease outbreaks early so that targeted WASH interventions can be deployed before epidemics take hold.

Governments and international organisations increasingly recognise that disaster risk reduction and WASH infrastructure development must be integrated. The WHO framework for managing environmental health risks in emergencies covers the entire cycle – prevention, preparedness, emergency response, and recovery – precisely because each phase influences the outcomes in subsequent phases.

What do you think? Should international agencies be held legally accountable when sanitation failures during disaster response lead to disease outbreaks, as in the Haiti cholera case? And how can communities in disaster-prone regions better prepare their water and sanitation systems to withstand future emergencies?

References

1. https://pmc.ncbi.nlm.nih.gov/articles/PMC558295/
2. https://www.who.int/teams/environment-climate-change-and-health/water-sanitation-and-health/environmental-health-in-emergencies
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC7170206/
4. https://spherestandards.org/handbook/
5. https://pmc.ncbi.nlm.nih.gov/articles/PMC4910130/
6. https://www.who.int/activities/managing-environmental-health-risks-in-emergency
7. https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5945a1.htm
8. https://pmc.ncbi.nlm.nih.gov/articles/PMC3381400/
9. https://www.cdc.gov/orr/responses/haiti-cholera-outbreak.html
10. https://www.ncbi.nlm.nih.gov/books/NBK54240/