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A chemical is a substance composed of chemical elements or a substance produced by or used in chemical processes. We use chemicals every day (home remedies, household cleaners), and they are a natural and important part of our environment. They help our plants grow (even poisonous plants) and fuel or cars. These hazardous chemicals also could be obtained and used to harm people, or they could be accidentally released. There are laws, regulations, guidelines, and recommendations concerning exposure limits and concentrations that can be regarded to be related to an acceptably low risk. A large number of products and many hazardous chemicals are manufactured, handled and stored within the chemical industry, and even other factories and work places (for example, chlorine, ammonia, and benzene). Communities in which industrial sites are located or through which hazardous material pass are at risk for technological disasters that may cause chemical emergencies. Some hazardous chemicals have been developed by military organizations for use in warfare, for example, nerve agents, mustards, and choking agents. It might also be possible for terrorists to get these chemical warfare agents and use them to harm people.
A chemical disaster/emergency occurs when a hazardous chemical has been released and the release has the potential for harming people's health (CDC - Chemical Emergencies, 2006). Chemical releases can be unintentional, as in the case of an industrial accident or a transport accident, or intentional, as in the case of a terrorist attack. The largest risk that a great number of people should be exposed at a chemical accident is by leakage of a condensed gas. It is stored under high pressure; thereby large amounts of gas in short time can be spread over large areas. In this connection is climate, such as wind direction, wind-force and temperature of great importance, but also the nature of the ground and buildings have influence on how the gas is spread. All of this must be considered when one should determine risk zones, and the triage and treatment area for injured.
Injuries can occur to workers at the site, to responders bringing the chemical accident under control and providing emergency medical care, and to residents in the community. Those with pre-existing medical conditions, such as lung or heart disease, could be at increased risk for worse outcomes if exposed to toxic releases. Burn, skin and eye disorders, and lung damage can result from exposure to specific agents. When caustic chemicals contact the skin or eyes, chemical injuries that destroy skin and tissue can occur. Air passages also can be injured by toxic fumes whenever a person’s skin is burned by chemicals. Consider possibility of exposure to inhaled toxins (carbon monoxide, chloroacetophenone, and methemoglobin) in both industrial and terrorist explosions.
A poison is any substance that impairs health and destroys life when ingested, injected, inhaled, or absorbed by the body in relatively small amounts. Under certain conditions, chemicals can be poisonous and harm people. Some toxicologists mean that, depending on dosages, all substances are poisons. The real concern is the risk or hazard associated with the use of any chemical substance. There are poisons that respond to specific treatments or antidotes and those for which there is no specific treatment. Today there are relatively few effective antidotes, and the treatment of poisoned persons is based mainly on eliminating the toxic chemical agent from the body before it can be absorbed. Maintaining respiration and circulation is the most important aspect of such treatment. Poison control centers provide information regarding all aspects of poisoning or intoxication, maintain records of their occurrence, and refer patients to treatment centers. Information about the clinical management of exposure to toxins can also be provided by CHEMTREC (a round-the-clock resource for obtaining immediate critical response information for incidents involving hazardous materials and dangerous goods), and industry databases.
Contamination is a condition of being soiled, stained, touched, or otherwise exposed to harmful agents, making an object potentially unsafe for use as intended or without barrier techniques. The body can be exposed to toxic substances by inhalation, splash into the eyes, contact with the skin or by ingestion. Waste due to leakage of condensed gas which is stored under high pressure can happen at an industry or by transportation. Even liquid substances can spread over a large area, especially at transport accidents. By sabotage or leakage to a water reservoir a large number of persons may be exposed to a toxic substance by ingestion. Potentially dangerous volatile substances should be used only in well ventilated areas. Because of their large surface area (body weight ratio) children are more vulnerable to toxicants absorbed through the skin.
The Bhopal disaster at the Union Carbide India Limited (UCIL) pesticide plant in Bhopal, Madhya Pradesh, India, on the night of December 2–3, 1984, was one of the world's worst industrial catastrophes. A leak of methylisocyanate (MIC) gas and other chemicals from the plant resulted in the exposure of hundreds of thousands of people. According to the mass media, the official immediate death toll was 2,259, later a total of 3,787 deaths related to the gas release were confirmed, and approximately more than 200,000 were injured.
The serious sarin attack (Subway Sarin Incident) on the Tokyo Subway in Japan, on March 20, 1995, killed 13 people, severely injured 50 and caused temporary vision problems for nearly a thousand others. It was an act of domestic terrorism, where the perpetrators in five coordinated attacks released sarin on several lines of the Tokyo Metro
On April 20, 2010 BP's Deepwater Horizon oil rig exploded in the Gulf of Mexico, killing 11 workers and commencing months of oil leaking unrestrained into the ocean. Several efforts to manage the spill were unsuccessful until BP capped the well in mid-July, temporarily halting the flow of oil into the Gulf. The well was successfully plugged on September 19, 2010. Oil hitting coastlines and the damage throughout the ocean posed a serious threat to fishermen's livelihoods, marine habitats, beaches, wildlife and human health.
Hazardous chemicals are often categorized by the type of chemical or by the effects a chemical would have on people exposed to it. The types used by the Centers for Disease Control and Prevention are the following (CDC - Chemical Emergencies, 2006):
The presence of a chemical agent does not exclude the simultaneous presence of a biological and radiological agent (Kales, & Christiani, 2004; Madsen, Hamaoka, & Hall, 2006).
Types of chemical agents most likely in an accidental release include:
Types of chemical agents most likely in act of terrorism or in warfare include:
Rescuers should be trained and appropriately attired before entering the accidental scene, hot zone, otherwise call for assistance from a HAZMAT team or other properly equipped response organization. Immediate decontamination of liquid chemicals may be one of the most effective and important life-saving measures that can be taken at the scene of an exposure. Removal of outer clothing can eliminate 85% to 90% of contamination (Kales, & Christiani, 2004). A variety of available chemicals could lead to eye and skin irritation as well as effects on the respiratory tract. Industrial accidents, train derailment or terrorist attacks may make staying put dangerous. During a chemical emergency people may have to evacuate or to shelter in place depending on where they live. Local police, emergency coordinators, or government on the radio and/or television emergency broadcast system will tell you if evacuation is necessary.
In the emergency department the chemical exposure is assessed. A quick but thorough assessment of chemical exposure victims can be performed by use of the mnemonic Asbestos (Madsen, Hamaoka, & Hall, 2006).
| Agent(s) | Type and estimated doses |
| State(s) | Solid, liquid, vapor, gas, aerosol |
| Body sites | Routes of entry (exposure, absorption) |
| Effects | Locals vs. systemic |
| Severity | Of effects of exposure |
| Time course | Sequence of events |
| Other diagnoses | Differential diagnoses |
| Synergism | Interaction among multiple coexisting diagnoses. |
Signs and symptoms of major chemical exposures (Kales, & Christiani, 2004):
Extremely high concentrations of chlorine or phosgene cause sudden collapse with clotting of blood in pulmonary vessels. High concentrations of cyanide or hydrogen sulfide and oxygen deficiency within a confined space, and exposures to VX or high-vapor concentrations or other nerve agents have also a hyperacute onset, while a hyperacute onset with vesicants are rare even with high concentrations. Most exposures to high concentrations of asphyxiant gases (carbon monoxide, cyanide) or oxygen deficiency, and riot-control agents, centrally acting pulmonary agents such as ammonia, hydrochloric acid, and chlorine can cause acute onset, typically within minutes to hours after exposure. Phosgene oxime, Lewisite, high concentrations of sulphur mustard (most likely agents in act of terrorism) may also cause acute onset, within minutes to hours after exposure (Kales, & Christiani, 2004).
There are two major types of pulmonary effects from toxic agents, referred to the two major physiologic divisions of the respiratory tract: The central or conducting compartment (tracheobronchial region), and the peripheral or gas-exchange (respiratory) compartment (Madsen, Hamaoka, & Hall, 2006).
Signs and symptoms of respiratory tract injury:
Chemical burn is tissue damage caused by exposure to a strong acid or alkali, such as phenol, creosol, mustard gas, or phosphorus. Chemical warfare is the waging of war with poisonous chemicals and gases, for example, nerve agents such as sarin and VX, mustards such as sulphur mustards and nitrogen mustards, and choking agents such as phosgene.
Carbon monoxide poisoning is a toxic condition in which carbon monoxide gas has been inhaled and binds to hemoglobin molecules, thus displacing oxygen from the red blood cells and decreasing the capacity of the blood to carry oxygen to the cells of the body. Carbon monoxide (CO) is a colorless, odorless, tasteless gas produced during the incomplete combustion of carbon and organic fuels, emitted in automobile exhaust fumes, space heaters and is find in smoke from fires. The affinity of hemoglobin for CO is 200 times that for oxygen. Usually the exposed victim of accidental inhalation does not realize what is happening until it is too late, and death occurs eventually if the victim is not removed from the source of the carbon monoxide. Warning signs include a sensation of pressure in the head and roaring in the ears. With acute poisoning, the patient shows confusion and inability to think clearly, and there will often be vomiting and incontinence, followed by convulsions and coma. Patients will not appear cyanotic despite the hypoxia, they may instead appear quite pink. Unconsciousness and apnea occurs in sequence as the level of carbon monoxide in the blood increases. Cherry-red skin is a late sign most commonly noted in fatalities.
Organophosphate poisoning is an adverse reaction to organophosphate pesticides such as malathion, chlorotion, and nerve gas agents. Organophosphates are a major component of many insecticides, and persons involved in the manufacture and use of these products are at risk for serious poisoning by absorption. Small children are also at risk if accidently swallowing the organophosphate. Many organophosphates are potent nerve agents, functioning by inhibiting the action of acetylcholinesterase in nerve cells. The organophosphates involves stimulation of the parasympathetic nervous system, including nausea, vomiting, sweating, epigastric and substernal tightness, abdominal cramps, headache, blurred vision, profuse salivation, and sometimes respiratory distress. Muscle twitching is common, weakness, and paralysis can occur. In severe cases, there may also be seizures and respiratory arrest.
Cyanide poisoning may occur through ingestion (bitter almonds, wild cherry syrup) or inhalation (gases generated in blast fumes, terrorist attacks); it can also be absorbed through the skin. When the exposure is massive, sudden fatal respiratory arrest may occur. The patient may be confused or stuporuos (classic odor of bitter almonds on the patient’s breath is suggestive). Respirations are usually rapid and labored in early stages, but later become slow and grasping. The pulse is often thready and rapid. Headache, vomiting, coma and seizures frequently occur. The patient’s venous blood may be bright red.
The goal in the management of the patient with a suspected toxic inhalation is to get the patient out of the environment of exposure and optimize his or her ventilation. If chemicals have splashed into the eyes, they must be flushed with copious amounts of water. Some poisons may gain access to the body by absorption through the skin. The goal of management is to remove the poison from contact with the body, and then copious flushing with a steady stream of water. The use of specific antidotes should not be considered until after copious irrigation with water has been accomplished. Ingestion to toxic substances is not that common in disasters. Your interventions should be within the scope of your professional license, skills and training, and when performed in a health care setting, adherent to the facility’s standard of practice.
The Hazardous Substances Emergency Events Surveillance (HSEES) system aims to reduce injury and death among first responders, employees, and the general public that result from releases of hazardous substances. It collects and analyzes information about acute releases of hazardous substances that need to be cleaned up or neutralized according to federal, state, or local law, as well as threatened releases that result in a public health action such as an evacuation.