HYDROFLUORIC ACID CAUSES DEATH OF SANITATION WORKER
BY PETER STUEBE
The potential for injury from inadvertent exposure to hazardous materials exists for many workers in our society, not just members of the emergency response community. A recent incident in New York City that caused the death of a sanitation worker illustrates that workers other than those in occupations generally considered at risk for exposure to hazardous materials also can be susceptible to harmful exposures. The incident also reminds us that as emergency response personnel, we must be ever vigilant in recognizing the presence of hazardous materials and protecting ourselves from them even in so-called “routine” situations.
THE INCIDENT
At this incident, a two-man sanitation truck was making its rounds in a Brooklyn neighborhood comprised of residential and some light commercial occupancies. As the hopper of the truck filled, one worker operated the controls to cycle the hopper. This brings the blade down and then inward, compacting the garbage inside the body of the truck and emptying the hopper for further collections.
Although Department of Sanitation guidelines call for workers to stand to the side of the truck as they operate the controls, workers sometimes continue to load garbage while the blade is operating. They do this to save time, expediting completion of the route.
In this case, as the worker stood in front of the hopper continuing to load garbage, the blade came down on a capped one-gallon plastic bottle. The pressure of the blade caused the bottle to compress. As it did, it burst open, showering the sanitation worker with liquid that soaked into his clothes.
He began to feel extreme pain in the areas where the liquid had contacted his skin. A volunteer ambulance corps happened to be quartered across the street. The burned sanitation worker ran to the ambulance building, where personnel removed his clothing and attempted to wash the unknown contaminant from his body. Additionally, a telephone call was made to 911, advising the operator that a worker apparently had been burned by an unknown chemical. Because the in-jury was a chemical burn, the sanitation worker was transported to the Burn Center at New York-Cornell Hospital.
Since the incident constituted a hazardous-materials emergency, the 911 call was routed to the fire department dispatcher. A normal first-alarm assignment of two engines, two ladders, and a battalion chief was directed to respond. Hazardous Materials Company 1 was also assigned because of the potential involvement of chemicals. On arrival, FDNY standard operating procedures (SOPs) for a suspected haz-mat incident were implemented. This calls for the first-due units to take a defensive posture and control access to the area, establish zones, attempt to identify the materials involved, and establish a water supply.
After interviewing the sanitation workers and the ambulance personnel and observing the truck from a safe vantage point, fire department members still were not able to identify the substance that had injured the worker. However, the situation at the truck was stable, the injured worker was in the process of being packaged for transport to the burn center, and no further information about what was in the truck could be retrieved without putting personnel in close proximity to the hopper. Thus, the incident commander decided to take no further action until Haz Mat 1 arrived.
When Haz Mat 1 arrived, a conference was held with the incident commander, the company officers, the Haz Mat 1 officer, the entry team, the uninjured sanitation worker, and ambulance personnel. All that was known was that some liquid had splashed out of the hopper while the blade was being cycled. This liquid had caused painful burns to the worker`s skin and was possibly a corrosive. To assist in the worker`s treatment, an entry would have to be made in an attempt to identify the liquid and mitigate the remaining hazard.
SELECTION OF PPE
At this point in the incident, Haz Mat 1 had to make some decisions regarding chemical protective clothing. It was clear that some type of respiratory and skin protection was warranted. Generally, a liquid/splash protective Level B-type suit is used when the liquid is unknown. For these types of entries, Haz Mat 1 carries three types of Level B suits: (1) a hooded suit of chemical protective material–the SCBA is worn on the outside; (2) a total encapsulating suit of the same material that provides better skin protection, particularly around the throat and face–the SCBA is worn on the outside; and (3) a simple raingear-type suit usually worn just to keep work/duty uniforms clean when dealing with fuel spills.
Because the entry would be in an outside area and there was little chance that significant concentrations of airborne material would build up, the entry team agreed on splash protection. They selected the total encapsulating version of the splash suit for several reasons: (1) the injury to the sanitation worker appeared to involve some type of corrosive liquid that obviously caused extreme pain on contact with the skin, warranting a high level of skin protection (although it was not yet known how grievously the worker had been injured); (2) the entry team was not only going to attempt to identify the material but also to mitigate the remaining product, if consistent with suit compatibility and neutralization protocols; and (3) typically, this part of the operation presents the potential for getting splashed with the corrosive liquid. Thus, the encapsulating splash suits were deemed to be the best choice.
Before an entry is made, FDNY protocols call for having a decontamination system fully set up and ready to go. The medical personnel who had decontaminated the injured worker indicated that the substance was water soluble, since it seemed to wash off his skin with water. Thus, since corrosives are generally water soluble, conditions called for a simple water wash with a liquid detergent. All our chemical protective clothing is of the single-use variety, which simplifies the decon operation, since clothing is not reused.
With an entry and backup team dressed and decon in place, the operation was ready to proceed. The plan called for an entry to attempt to find the container that held the liquid that splashed over the sanitation worker. Since it appeared to spray over him with some force as the blade cycled, it was believed that a plastic bottle may have been crushed–an occurrence to which we had responded many times. This assumption is also consistent with the fact that corrosives are commonly shipped in plastic bottles. (Corrosives are sometimes shipped in glass bottles, but the manner in which the liquid sprayed out seemed to indicate that the container was made of plastic.) With this minimum of information, the entry team began the operation.
ENTRY
All members of Haz Mat 1 are trained to operate the controls of city sanitation trucks, since they frequently respond to incidents involving these trucks. Our SOP also stipulates that the member operating the controls is to stand to the side of the hopper when releasing the compacted trash for examination; the second member of the entry team and the haz mat officer are to observe the operation from a safe vantage point. Usually, a small amount of trash is released at a time so that the entry team can look through a manageable amount at one time. Also, assuming that the material that caused the problem is close to the rear of the truck, just inside the hopper, responders will not have to look through more garbage than necessary.
Fairly quickly, a suspect bottle was found and examined. The label on the bottle read “hydrofluoric acid, 70%.” The bottle was washed off with water, brought to the edge of the hot zone, placed inside a plastic bag, and then examined by the haz mat officer. The entry team also tested the liquid on the ground and in the hopper with pH paper, which indicated that the substance was an acid.
Resource material indicated hydrofluoric acid (HF) to be a fuming colorless liquid with a strong pungent odor. Significantly, it has a vapor pressure of 110 mm Hg, indicating it will vaporize quickly (about four times faster than water, as a comparison), and the vapors are heavier than air. HF has an OSHA (Occupational Safety and Health Administration) PEL (permissible exposure limit) of three parts per million (ppm) and an IDLH (immediately dangerous to life and health) level of 30 ppm, indicating a severe health hazard. Skin contact causes severe chemical burning of the skin and severe irritation of any exposed tissue. Tissue necrosis (death) can continue through the layers of skin and fatty tissue until bone is reached. All the available information indicated we had found and positively identified the material causing the problem as hydrofluoric acid.
At this point, this information was given to the Bureau of Emergency Medical Services (BEMS) for transmittal to the burn center. This allowed the medical personnel to treat the injured worker with calcium gluconate, which attaches to the fluoride ion in an attempt to bind to it and stop it from further destroying tissue. However, in spite of being given the best possible care, he succumbed to his injuries several hours later, due to the acid`s toxicity and concentration and the extent of his exposure. Ultimately, the cause of death was heart failure, caused by the fluoride ion`s effect on the calcium ions that are part of heartbeat regulation.
SUIT COMPATIBILITY
With the material identified, the next step was to deal with the acid in the truck`s hopper and on the ground. We needed to determine whether the encapsulating suits being worn by the entry team would provide adequate protection from 70-percent hydrofluoric acid or whether another suit had to be used. In such situations, a suit compatibility chart must be consulted to get the manufacturer`s test data for the particular challenge chemical. The breakthrough times are listed in the box on page 120.
Unfortunately, the suit material was not tested against the 70-percent concentration we had. At this point, knowledge of test conditions and interpolation of the data are necessary because the specific data we needed were lacking. These permeation tests are done at 100 percent concentration of the challenge chemical. Since responders could come in contact with 100 percent product while performing mitigation (the product being the HF liquid, 70 percent), the test conditions represented our situation for this variable. But although the suit material was not tested against 70-percent HF, the chart showed an actual breakthrough time of 67 minutes for the 90-percent HF. Since 70-percent HF is less concentrated than 90-percent HF, it should permeate the suit material less quickly than the higher concentration. Thus, we reasoned that we would have more than 67 minutes until breakthrough when dealing with the 70-percent HF.
Our SOPs call for entry times to be limited to about 20 minutes, unless a job can be completed in a few more minutes and an additional entry can be avoided. This limiting of our entry time served to be an additional safety factor, further increasing our comfort level.
INCIDENT MITIGATION AND TERMINATION
The information on suit compatibility was relayed to the entry team, which then continued its search for any additional bottles that may have been in the truck. Not finding any, the next step in the operation was to mitigate what had been spilled. If possible, the preferred method is to recover what is spilled and then dispose of it properly. In this operation, recovery was impossible because of the large amount of garbage sprayed with HF and the volume of liquid in the hopper.
After concurring with the Department of Environmental Protection (DEP), neutralization–using standard soda ash (sodium carbonate) to neutralize the acid–was determined to be the better course of action. The soda ash is usually first dissolved in water, and the resulting slurry solution is then added to the acid to be neutralized. We have found that this method gives us better control over the resulting reaction and reduces the chance of overneutralizing, which could result in our ending up with a strong base that also would have to be mitigated.
Since there usually is a lot of liquid in a sanitation truck hopper, the only method for determining where the HF has spread is to use pH paper to test all suspected wet areas. In this way, the entry team would have to neutralize only contaminated areas. The street and the ambulance also had to be decontaminated as part of the operation–a time-consuming, but not difficult, procedure. As areas with an acidic pH were identified, the soda ash solution was applied until the pH was as close to neutral as practicable. Ideally, a pH of seven (neutral) is desired, but the pH can easily be overshot, making the area too basic. Thus, close to neutral is acceptable.
Additionally, Haz Mat 1 was requested to determine the condition of the emergency room at the burn center, which had been isolated and not used by patients and staff because it might have been contaminated. Haz Mat 1 checked the pH of the areas in which the victim had been treated and found no contamination; as a precaution, however, the entire area was rinsed with plain water to ensure that no residual HF was present.
Finally, the ambulance that transported the victim was thoroughly decontaminated and rinsed. At this point, the incident was deemed to be over, and the units began to return to service.
A subsequent investigation by several city agencies was not able to determine the source of the hydrofluoric acid that was dumped into the garbage. It could have come from any occupancy along the route or might just have been placed in an existing pile of trash. Unfortunately, those responsible for the worker`s death likely will never be held accountable. n
n PETER STUEBE, a 21-year veteran of the Fire Department of New York (FDNY), is a battalion chief assigned to the Bronx. For five years, he was the captain and commanding officer of Hazardous Materials Company 1. He is also a member of the Westchester County (NY) Hazardous Materials Response Team and a former haz mat instructor at the FDNY Bureau of Training. He has a bachelor`s degree in business from Marist College, a master`s degree in economics from Pace University, and a master of public health degree in environmental health sciences from Columbia University. Stuebe is an adjunct instructor at the National Fire Academy, teaches at the City University of New York, and is an editorial advisory board member of Fire Engineering.
