By WILLIAM R. KERNEY, MA, EMTP (Ret.)/College of Southern Nevada
Vapor clouds can be dangerous. Responders never want vapors wafting toward them when pulling up to an emergency. When threatened by a vapor cloud, standard rules should always apply. Protect oneself, contain the incident and stay up wind and on high ground for a start. With a vapor release, calculate the rate of movement and change assessment of hot, warm and cold zones based on that movement.
This is a major problem for extinguishment and rescue in handling the incident. It also challenges the police charged with the evacuation and movement of the citizenry.
Containment of an industrial facility may be simple based on physical barriers. The vapor cloud may not drift to a surrounding community. An uncontained vapor cloud release increases the overall risk for potential injury to the adjacent civic areas.
Vapor clouds come in all shapes and sizes. They can be made up of a variety of materials, all readily found in industrial complexes, aboard ships, and even resulting from mishaps in the home. Have you ever made the mistake of combining chlorine bleach with ammonia in your washing machine? I have, not knowing my wife had already added ammonia in the machine. I put bleach into a load of whites and was nearly killed by the green cloud of chloramine. For you chemists and my IFW colleague John Townsend, it comes down to 2NH3 + Cl2 ‡2NH2Cl.
In general, identify the chemical compound creating the cloud. However, for EMS providers, this is not essential in the short term. Initial responses must include removing the victims from the contaminated atmosphere and administering oxygen, as long as there is no immediate danger to the EMS providers themselves. Remember, your safety is first.
Hazardous Materials Classifications are as such:
• Explosives • Toxic & Infectious Substances
• Gas • Radioactive Materials
• Flammable Liquids • Corrosives
(100 degrees F or less, • Miscellaneous
closed cup) • Dangerous Goods
• Other Flammable • Oxidizing Substances
Substances & Organic Peroxides
Any of these substances above have the potential for the formation of a vapor cloud. Much of that depends on altitude, boiling point, density and evaporation rates. What is a good EMS provider to do when pulling up on a vapor cloud in progress? What is the substance? What are the chemical properties? Stay away, contain the incident, notify hazmat and get further help started into the scene. Keep others away as well. Assist in containing the incident without compromising personal safety if possible.
When substance identification is not readily available, find high ground upwind. I have seen a chief officer stage his personnel in a low-lying area, only to have to move them quickly. The vapor proved to be chlorine, which is heavier (denser) than air. An ugly pale blue cloud sank into the low-lying staging area. Remember you are responsible for your own safety. Always question orders that may be problematic.
When dealing with vapor cloud victims, common issues include inhalation injuries and eye and skin contamination or contact. The injuries sustained will depend on the chemical, the physical closeness of the incident and length of exposure. Triage may be necessary depending on the volume of victims.
Inhalation signs and symptoms may include:
• Respiratory distress including related chest tightening (chest pain and dyspnea), laryngospasm and airway constriction. Increased respiratory rates and possible cyanosis are expected.
• Increased lacrimal secretions (tearing) and rhinitis (runny nose).
• Corrosive chemical burns to the nose and mouth.
• Drooling and diaphoresis.
• Pulmonary edema with some exposures.
Skin and eye signs and symptoms may include:
• Burning pain, redness and related inflammation.
• Deep burns and possible skin discoloration.
• Eye burning or discomfort and clouding.
• Spasmodic blinking or involuntary eye closing with related redness and tearing.
• Depending on the chemical, frostbite “burns” may be included in the overall assessment.
When presented with victims of a chemical vapor cloud, following decontamination if indicated, treatments should focus on supportive care. Stick to the basics here:
• General impression.
• Assess mental status using the AVPU scale — Alert, Voice, Pain, Unresponsive.
• Assess airway and make all necessary therapeutics to sustain same.
• Check breathing and administer oxygen and respiratory support as necessary.
• Check circulation – start CPR as necessary.
• Flushing eyes and skin with water may help to dilute the offending substance and offer analgesic relief.
Remember in mass casualty situations, the triage of the victims may require closing the book on most, if not all, severely compromised victims. Do not make the mistake of committing precious resources on victims that have little or no chance for survival.
Certain chemical exposures require very sophisticated therapeutic measures to sustain the victims that may not be readily available to the general EMS community. Hydrofluoric acid (HF) may require calcium gluconate injection at the local exposure site, and administration of gluconate gel for topical or skin injuries. Nebulizer administration of same for inhalation injury may be indicated. Industrial battalions may have this readily available but municipal responders supporting the incident may not. Get medical direction. The local industrial facility may be able to provide calcium gluconate.
With cyanide, the same issues arise. Treatment therapeutics may not be readily available except possibly with the industrial brigade and may be in limited supply. Cyanide requires amyl nitrate administration via the respiratory tract as well as intravenous administration of sodium nitrate and sodium thiosulfate. While these are in the cyanide antidote kit, the kits themselves do not have a long shelf life (meaning multiple years) and often expire.
Kit expiration issues in Chicago were exactly the case after the Tylenol cyanide deaths of the 1980s. All Chicago fire ambulances were issued cyanide antidote kits and most, if not all, expired before they were used. When faced with the financial burden of replacing the kits, the issue became cost prohibitive.
Remember, in cyanide poisonings do not use the pulse oximeter for measurement. Cyanide does not act like carbon monoxide by taking up hemoglobin space on the red blood cells. Instead, it prohibits the off-loading of oxygen at the cellular level. A pulse-ox reading of full saturation of the red blood cells in the case of cyanide poisoning is a useless measurement.
When faced with the chemical vapor cloud, make the appropriate notifications, protect yourself and your crew by staying up wind and up hill, keep the related citizenry away, guesstimate wind speed and direction, and plan for the worst. In an industrial accident, containment is a priority. In the case of terrorism, remember to address panic. Keep a cool head. Think, and remember personal safety.