3.3.1 Chemical accidents

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The production of chemical products goes hand in hand with industrial growth and development. In addition, the transportation of chemical substances has increased, both within countries and internationally. Natural hazards such as earthquakes can lead to emergencies if they cause leaks or spills at plants that produce chemical products.

Human settlements located close to industrial plants are very common in developing countries, which makes the populations involved more acutely vulnerable to the hazards of chemical accidents.

Chemical products pose potential health risks if they leak or spill, either due to accidents in processing plants or because of human error in managing the safety mechanisms involved in complex industrial processes.

An example of note is what occurred in Bhopal, India, where a leak of gas and other chemicals from a pesticide plant killed thousands of people, in addition to exposing and affecting hundreds of thousands.

For more information we recommend:

  • The chemical catastrophe of Bhopal, a well-documented account of the disaster, and
  • The India Environmental Portal of the Centre for Science and Environment, which marks the 25th anniversary of the disaster by publishing a selection of interesting information on the follow-up to the Bhopal accident.

Depending on their particular characteristics and properties, chemical substances can cause explosions and fires, disperse toxic smoke in the atmosphere, or pollute the environment, water, and soil.

For the purposes of emergency information and action, in the field of transportation in particular, the United Nations classifies substances into the following groups according to their properties:


- gases
- flammable liquids
- solids that represent a fire hazard

Oxidants and organic peroxides:

- toxic and infectious substances
- radioactive substances
- corrosives

From a public health perspective, the effects of chemical substances can be acute or chronic. This depends on the type of substance, its physico-chemical properties, toxicological properties, the quantity released, exposure time, and the channel of exposure. Toxic chemicals can jeopardize health through inhalation, contact, ingestion, or ocular exposure, and can be harmful to the respiratory system (lungs in particular), create neurological or immunological damage, and cause cancer or teratogenic effects.

The environment, and soil and water tables in particular, can be contaminated by the degradation of chemical substances and compromise the health of the population through the ingestion of contaminated food or water.

The Region of the Americas has experienced cases of poisoning from chemical products, such as the massive poisoning by methanol consumption that occurred in Nicaragua and Ecuador. Consult the U.N. Environment Program’s Flexible Framework for Addressing Chemical Accident Prevention and Preparedness.

In view of the growing exposure to these hazards, the Andean countries prepared an Andean Subregional Plan for the prevention of and response to emergencies due to hazardous chemicals and radioactive substances (available only in Spanish), which provides an assessment of what work must be done in Bolivia, Colombia, Ecuador, and Peru.

In terms of preparedness and response plans, dealing with toxic chemical accidents requires broad multidisciplinary and interinstitutional involvement that addresses:

  • safety measures in production plants;
  • safety in transportation and storage;
  • appropriate equipment for decontamination activity;
  • practical information for populations living in the vicinity of chemical plants;
  • specialized response mechanisms, both for toxicological clinical management and for appropriate management of the substances causing an emergency; and (g) training of specialized personnel.

For complete information about chemical hazards emergency medical management, consult the website of the U.S. Department of Health and Human Services.