Contaminated, self-referring WMD victims could create a moving warm zone, making appropriate PPE a crucial matter for EMS and healthcare personnel.

One assumption of disaster response is that emergency medical personnel will perform triage, decontamination and transport of victims, even though field experience tends to show otherwise.

Disaster plans may specify that casualties be triaged in the field, but studies show that survivors often bypass field first aid, because victims may not know triage stations exist or where the stations may be. A 2004 study (Prehospital Disaster Medicine, 2004; 19:213–220) on mass-casualty incidents between 1993 and 2000 involving hazardous materials found that one-third of those decontaminated were not decontaminated in the field.

In the event of a WMD attack, there is no reason to believe that decontamination stations set up by responders would not likewise be bypassed. In the aftermath of the 1995 Tokyo subway sarin attack, 80% of victims self-referred to hospitals without being field decontaminated.

"In many documented cases, current response assumptions are simply not true, and several incidents have shown the potential to adversely affect EMS and hospital personnel before the perceived need for personal protective equipment even exists," says Andrew Garrett, M.D., director of planning and response for Columbia University's National Center for Disaster Preparedness.

This tendency of WMD victims to elude emergency services would surely put healthcare providers at risk, possibly before they have time to initiate PPE protocols. After the Tokyo sarin attack, 135 prehospital and 100 hospital workers reported symptoms consistent with nerve agent exposure, including 11 physicians, six of whom required antidotal therapy.

Exposures to hospital staff usually result from proximity to or contact with a patient whose skin or clothing is contaminated.

"There is a lack of definitive scientific proof specific to choosing PPE for healthcare professionals who will be needed to care for contaminated wmd victims," says Russell Bennett, professor of health policy and management, Jackson State University. "A minimum of Level C PPE is assumed to be adequate, but is that enough?"

Field of seams
"Since there is currently no national standard specifying Level B or Level C, most groups are now training hospital and prehospital hazmat teams at Level B and medical providers at Level C," says Susan Miller Briggs, M.D., assistant professor of surgery at Harvard Medical School and director of the Trauma and Disaster Institute, Harvard Medical International.

The current OSHA hospital recommendation is Level C with powered air-purifying respirators. The basic assumption is that Level C protective equipment would be used in circumstances where the type and concentration of chemical or biological agents has already been determined. But there is lingering concern regarding the use of Level C protective equipment where an immediate response is required, especially if the causative agent has not been identified.

"At the least, it should be kept in mind that Level C protective equipment may be ineffective, and if symptoms of secondary exposure appear, the level of protection should be increased," Bennett says.

Hospitals have received federal aid to initiate bioterrorism hospital preparedness programs. Funding and training have increased for FEMA's Urban Search and Rescue Task Forces, and for Health and Human Services' Disaster Medical Assistance Teams. Still, what meager WMD PPE currently exists in hospitals scarcely begins to match the potential need.

"Fewer than 6% of hospitals are wmd prepared, including on-site, tested and ready-to-use Level C PPE and decontamination equipment," says Maurice Ramirez, D.O., founding chair of the American Board of Disaster Medicine.

The right cuff
Hot zone emergency response to hazmat releases, including CBRN, is specified under OSHA's Hazardous Waste Operations and Emergency Response (HAZWOPER) regulation, 29 CFR 1910.120 (q). NIOSH has also developed a respiratory protection approval specifically for CBRN exposures, as has the Department of Homeland Security.

Guidelines for warm zone activities, however, have been slower to develop.

"Lack of data and historic reliance on hazwoper standards for hot zone entry has hampered consideration of warm zone exposure," says John L. Hick, M.D., an emergency physician at the Hennepin County Medical Center in Minneapolis.

Some had suggested a special "Level H" protection for warm zone healthcare workers, although OSHA's 2004 first receiver guidance document generally quashed that debate. The OSHA document addresses effective ways to prepare for a mass-casualty incident following a major disaster, including alternate methods for worker protection, PPE, decontamination and training requirements.

Before the OSHA document, it was thought that there should be a separate level of protection for hospital workers, one that didn't fit traditional hazwoper definitions.

After the 2003 sars outbreak, many hospitals began moving in the direction of widespread universal precautions, including N95 masks, barrier wear and papr units for staff.

"For WMD, hospitals are now moving uniformly to Level C with multi-filter paprs, which are usually preferred over aprs [air-purifying respirators] due to comfort and fit-testing issues," Hick says.

Many healthcare providers understandably feel uncomfortable wearing hot, cumbersome, confining PPE that restricts tactile sensations and inhibits communication with patients and staff, all of which points to a critical need to find ways to improve the technology.

"We need to find ways to allow better tactile movement, and reduce restriction of heat loss caused by the garment's high insulation and low permeability to water vapor," Bennett says.

What's hot
While most new developments in PPE relate to improvements in comfort or performance in existing equipment, few of them were designed with healthcare in mind. Nevertheless, there are several promising technologies to look for down the line.

Nanotechnology, the manipulation of material at the microscopic level, may one day be standard in some PPE.

"In a firefighter's turnout gear, for example, nanotechnology fibers would 'sense' ambient temperatures and adjust themselves accordingly," says Christopher Reynolds, a professor of critical infrastructure studies at American Military University.

Nanotechnology would also permit fibers to release charcoal or other neutralizing agents when they sense toxic chemical agents, Reynolds says.

While these future technologies may seem promising, some experts believe that for any future or even current PPE to be most effective, it will first be necessary to determine where exactly warm zones begin and end.

Garrett says it's far more important to look at the decision-making that deals with the use of PPE by healthcare workers than it is to move newer technology into the hands of the average hospital and ems worker.

Classically, the warm zone is a tidy circle drawn around a contaminated area that serves to buffer the hot zone from the cold zone. While this works well for a chemical spill at a train wreck, it's more difficult to apply practically if the hot zone is widespread or unknown, as would likely exist in a wmd event.

The prevailing assumption is that hospital emergency departments and ambulances exist by definition in the cold zone, and if they were to become contaminated they would simply be put out of service. Current evidence has established that this is neither realistic nor practical, because the movement of contamination on the bodies of self-referring patients essentially creates a migrating warm zone.

"The reality is that many emergency departments and ems units, despite the best intentions and preplanning, will become warm zones because we simply may not know that a patient is contaminated until after we begin treating them," Garrett says. "Accepting this is difficult, because it goes against the way that we were all trained, and it also acknowledges that there is in fact additional risk to working in this type of setting when dangerous substances are involved."

EMS issues
Appropriate PPE for perimeter control and ems warm zone operations remains in flux.

EMS personnel are always among the first to respond in the event of a disaster. However, EMS is also among the least supported of all public safety agencies across the nation, lacking both adequate training and proper equipment for disaster response.

According to a 2005 report by New York University's Center for Catastrophe Preparedness and Response, more than half of EMTs and paramedics have received less than one hour of training in dealing with chem-bio agents and explosives since the 9/11 terrorist attacks, and 20% have received no training whatsoever. Moreover, in 25 states, fewer than 50% of EMTs and paramedics have adequate equipment to respond to a biological or chemical attack.

Prehospital PPE often depends on the role of the ems provider in community hazmat events. "Traditionally, Level C has been advised, but recently this has shifted toward Level B PPE in some circumstances," Ramirez says.

OSHA requires use of Level B for first responders until monitoring reveals concentrations to be below the threshold required for safe use of an APR. This requirement presents difficulty for ems, because the agent is often unknown at the time that medical care is provided in the warm zone.

Hick says in most cases, EMS could operate in the warm zone with the same PPE that's currently recommended for hospitals (Level C), provided that the warm zone is warm only because of secondary contamination from the victims themselves. But some EMS systems have been reluctant to commit to the training time and responsibilities that come with Level B PPE.

"It is easier in fire-based ems services that routinely use Level B, but not so easy when EMS is private," Hick says.

OSHA is expected to issue guidance on this topic sometime in 2007.

To protect and serve
Since public safety responsibilities tend to merge during crises, the PPE discussion has widened to include agencies other than hazmat and fire.

"I see a blurring of the boundaries between traditional roles of firefighters, hazmat and law enforcement," says Philip Mattson, program manager for critical incident technologies at the National Institute of Standards and Technologies.

When police take down a meth lab or respond to a WMD incident, they may need some type of chemical protective equipment. WMD events, of course, complicate conventional response for everyone.

"Hazmat teams working at an industrial site usually know what sort of toxicity they're dealing with and can dress accordingly," Mattson says. "Routine incidents that hazmat teams respond to every day have their protection levels predetermined."

The problem that wmd events introduce is that agencies are often forced to work in each other's areas and their primary-task PPE may not be sufficient, plus adequate training may be missing.

"This is particularly true in rural areas, where funding is tight and federal funds have yet to materialize, but the reality is in most of the country there is an inadequate cache of PPE for local disasters," Reynolds says.

Adequate training, a vital component of WMD preparedness, is also often missing. PPE appropriate for decon operations in a weak warm zone is not appropriate for hot and even other warm zone applications.

It's one thing to order equipment and stash it on a shelf, but it's another altogether to make it part of a maintenance, education, training, drilling and community response program that will ensure that it actually offers benefit to the user and community.

"Too often we see paprs and other equipment deployed in hospitals and on rigs with too little training," Hick says. This can lead to ineffective use of the equipment, non-use when it should be applied, or worse yet, use in an environment for which it wasn't designed.

It's also important that the community have well-defined roles of who will do what and what protections are needed to accomplish this.

"In the past, ems often assumed they would only see 'cold' casualties, but this doesn't happen," Hick explains." Hospitals assumed in many cases that fire departments would do their decon, but this doesn't usually happen either."

Defining the expectations and resources in the community and closing PPE gaps where they exist is also critical.

"You don't want to jump to a higher level of PPE than you really need, because higher levels of protection introduce canister refilling, weight, physical stress, training and other limitations," Hick says. Generally, as the level of protection increases, mobility, dexterity and vision decrease.

The key, he says, is the right protection for the right mission at the right time.