Environmental emergencies: weighing the ounce of prevention

Poison exposures 

Your discussion with these parents might begin with the problem that brought them to the ED. The American Association of Poison Control Centers (AAPCC), 64 participating poison control centers that serve an estimated 98.8% of the US population reported over 2.2 million poison exposures in 2001. On average, poison centers handled a poison exposure every 14 seconds. Nearly two-thirds of the calls concerned children < 20 years of age, and these exposures tended to cluster according to a typical bimodal distribution of age: one peak in toddlers (1- and 2-year-olds, 33% of all calls), another in adolescents (13- to 19-year-olds, 7.3% of all calls). Exploration, not impulse or intent, characterizes the more common toddler exposures, which tend to be less severe than adolescent exposures (1.2% and 7.2% of 1074 fatalities, respectively, in 2001). The majority of poison exposures occurred via ingestion, accounting for 75.8% of all calls and 77.1% of fatalities; inhalation represented 6.3% of calls and 9.4% of fatalities.1

Drowning or near-drowning 

Because the family owns a swimming pool, you ask the parents about precautions they have taken to prevent drowning. Drowning is defined as submersion with subsequent asphyxiation and death. The term near-drowning is used to describe victims who survive at least 24 hours after submersion.8 According to the Centers for Disease Control and Prevention (CDC), drowning claims the lives of approximately 4000 people each year in the US, and although probably under-reported, near-drowning may have significant associated neurologic and pulmonary morbidity.9

Drowning does not occur evenly across the age spectrum of childhood. There is a bimodal distribution, with peaks associated with toddlers and older teens.10, 11, 12 Male gender is another risk factor, as is African-American race in the US.10, 13 A number of studies have attempted to define various descriptors of childhood drowning, including age, gender, race, and location. An understanding of these is necessary in order to institute effective prevention strategies. Several studies emphasize that primary prevention measures must consider the location of submersion, a critical aspect of drowning, in order to become effective. In one study, the investigators reviewed death certificates for 1400 children under the age of 20 years who were victims of unintentional drowning in the year 1995, and found a fairly typical pattern of age versus site that is duplicated in other studies. The majority of infants drowned in bathtubs and buckets. Children 1 to 4 years of age tended to drown in artificial pools, while the majority of older children drowned in natural bodies of freshwater.12 Another study of drownings in children aged 0-14 years in the United Kingdom (UK) compared numbers of cases in two time periods 10 years apart. Despite a 6% rise in population over the decade, 104 children drowned from 1998-1999 compared to 149 in 1988-1989. Whether this significant decrease was the result of improved supervision or less-accessible pools, the numbers actually rose for garden ponds, which have become increasingly popular in that country despite their obvious threat to toddlers. Swimming pools in hotels or apartments abroad were also associated with significant numbers of drownings in the more recent period. There were three times as many male victims as female in both periods, and—although the numbers are small—there are indications that autistic spectrum disorder confers additional risk.14

Other studies have evaluated the efficacy of fences in preventing drowning deaths. For example, fencing ordinances enacted in the first half of the 1990s in Los Angeles County did not appear to reduce the rate of childhood drowning in residential pools. It is unknown whether this failure was the result of inadequate enforcement, inadequate operation/maintenance, or building codes that allow 3-sided fencing. The latter codes permit a building wall, even if it contains accessible doors or windows, to act as one side of the pool barrier.13 However, Thompson and Rivara15 found that pool fencing did reduce the risk of drowning, acknowledging that isolation (4-sided) fencing is superior to perimeter (3-sided) fencing (OR for the risk of drowning, 0.17; 95% CI 0.07, 0.44).

The parents tell you that a 4-sided fence, including a self-latching gate, surrounds the pool. You caution them to lock the gate when the pool is not in use. They do not own a solar pool cover, but you note that these devices, designed to float on the surface of a pool and passively absorb heat, have been associated with drowning when people or pets become trapped under the cover.16 The parents have considered the purchase of a pool alarm, but are not familiar with a study released by the US Consumer Product Safety Commission (CPSC) that compared the efficacy of three types of alarms. When an object falls into a pool, waves are generated that trigger either floating or underwater alarms, while water exposure triggers wristband alarms. The study found that underwater alarms detected waves from objects falling into a pool most reliably, and were least likely to signal a false alarm. Wristband alarms were deemed least practical, as they could be effective only if caregivers remembered to attach them to children, and alarmed after exposure to any water source.17 The parents then ask whether swimming lessons could protect their son from drowning. A number of organizations offer aquatic programs for infants and toddlers. The popularity of these programs is no doubt on the rise, but their purpose is less clear. Do children enrolled in these programs acquire swimming skills more rapidly? In a recent position statement, the American Academy of Pediatrics (AAP) summarized the relevant literature. Most experts agree that children who are younger than 4 or 5 years of age lack the neuromuscular capacity to learn traditional swimming strokes, and there is no evidence that early introduction to lessons means improved skill acquisition. Are children who have completed these programs less likely to drown? It is conceivable that their parents may feel a sense of complacency about their abilities to remain safe in and around water. In fact, there is no convincing evidence that aquatic programs mitigate the risk of drowning among infants and toddlers. Children in this age group probably lack the cognitive skills to comprehend water hazards. Continuous and close (preferably within an arm’s length) adult supervision has no substitute in the prevention of drowning.17, 18

Do other supervisors, such as lifeguards, make a difference in other settings? According to the CDC, lifeguards do play an important role in the prevention of drowning. The chance of drowning at a lifeguard-protected beach may be less than one in 18 million. A CDC working group, noting that victims rarely call for help or otherwise attract attention, recommends that lifeguards have no distractions while on duty. Lifeguards may also have a policing role in preventing behaviors that put swimmers at increased risk for drowning.19

Radiation 

Finally, you attempt to answer the parents’ questions about radiation from nuclear power plants or terrorist acts. In 1986, operators conducting a test of the Chernobyl (Ukraine, former Soviet Union) nuclear power station ignored safety procedures designed to control the nuclear reaction. This allowed a runaway reaction to occur in the facility. The reaction progressed to the point that steam pressure rose and eventually exploded through the top of the reactor, while a fire ignited and burned for days.20 Unlike the vast majority of US nuclear power plants, which have redundant steel-and-concrete containment shells and cooling mechanisms, the design of Chernobyl-style reactors required a structure too tall for containment shells.21 This design feature, along with the operator’s error, contributed to the explosion and fire that generated the largest known release of radioactive material, contaminating 21,000 square kilometers and exposing an estimated 17 million people. Although its half-life is only 8 days, high levels of the radioactive isotope iodine-131 were present in the immediate and downwind areas for three months after the event. Young children are particularly susceptible to this isotope, as their thyroid glands take up iodine from environmental sources. Of the individuals exposed, 2.5 million were children under the age of 5.22, 23

Reports of increased frequency of thyroid cancer in children living or born in areas of highest radioactive contamination began approximately 5 years after the Chernobyl disaster.24 Following events that release short-lived radioactive isotopes of iodine, a prophylactic dose of stable potassium iodide (KI) will effectively block thyroid uptake of radioactive iodine isotopes. After Chernobyl, for example, 16 million individuals in Poland received single prophylactic doses of KI with minimal side effects, an act of prevention that probably reduced the projected radioactive iodine dose by 40%.21

Once-unthinkable terrorism is now a reality in the wake of events such as the sarin attack in Japan, and the September 11 attacks in the US. In an effort to accomplish their goals, terrorists may employ weapons of mass destruction, including biological, chemical, and nuclear agents, which have the potential to generate environmental emergencies on a broad scale.

Concerns have arisen over the possibility of terrorists using a “dirty bomb,” which employs conventional explosives to disperse radioactive material over a small area. Such devices are meant to instill fear but are unlikely to contain high-grade radioactive material, and therefore would not threaten individuals beyond the area of the blast itself. If a terrorist attack were, however, to involve a nuclear weapon or power station, an ensuing fission reaction could potentially release high-grade radioactive isotopes into the atmosphere, posing a potential toxic threat to populations in the immediate vicinity and downwind of the site. Some municipalities that are potential terrorist targets, or are located in the vicinity of nuclear power stations, have begun to stockpile or distribute KI. But you caution the parents that KI is no panacea: in the event of a radioactive blast, KI would protect only the thyroid gland. Local emergency management officials would have to determine first whether radioactive iodine is present among a range of possible isotopes before recommending that individuals take KI.25 Complete dosing recommendations for KI are available from the US Food and Drug Administration.26 You suggest that the parents inquire about KI distribution plans at their town hall.

You also point out that although terrorism may emerge from a complex interplay of centuries-old forces, it may generate immediate chaos that overwhelms regional and local hazardous materials (HAZMAT) and emergency medical services (EMS) teams. These teams are responsible for the triage, decontamination, and treatment of victims who may have been exposed to the agent in question. In addition, individuals may play a role in protecting themselves: the CDC recommends three basic measures that would reduce an individual’s exposure in a radiation emergency: (1) decrease the time spent near the source; (2) increase distance from the source; and (3) increase shielding between the individual and the source.25 The avoidance of radiation-contaminated food has also been recommended.23

And what about gas masks? The parents ask whether they should outfit the family in preparation for a terrorist attack involving biological or chemical agents. You note that most experience with gas masks is found in occupational settings, and that there is little in the way of medical literature regarding civilian populations. The medical corps of the Israeli Defence Forces published an article that describes their effort to identify members of the Israeli civilian population—including children, the elderly, and the sick—who might have difficulty using gas masks issued prior to Operation Desert Storm.27 You reassure the parents that you are aware of no official recommendations to issue gas masks to the general US population.