8 Lessons From a Nitric Acid Response

By Kevin Ryan

On May 19 around 0655, Baltimore City Fire Department responded to a local chemical company for a reported nitric acid leak. A hazmat tactical alarm was struck for E-35, T-6 and Hazmat 1. SOC-4 was added to the call as well. SOC-4 was first to arrive at the facility gate.

Command was established, and staging for incoming units was set up at the main gate. Command located the incident in the northwest portion of the facility near the bulk storage tank farm.

A vacuum truck holding 68% nitric acid (non-fuming) was leaking from a gasket at the double check valve (see the BCFD nitric acid chemical card). The gasket was on the wrong side of the valve and the leak could not be controlled with the valve.

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The vac truck was already placed in a containment pool, as the truck was being used to store the nitric while the bulk storage tank was serviced. The containment pool was more than sufficient to hold leaking product during the initial stages. The rate of the leak was about 1 gallon every 5 minutes.

Initial worker accountability check, and later, a more thorough accountability check were completed; all workers accounted for in both checks. Plant personnel handed over an SDS for nitric acid almost immediately upon request.

Command began setting up a hot zone to isolate the leaking truck. The ERG recommends a 150-foot area be set up as the initial hot zone. The hot zone was determined by using the layout of the plant to isolate the area. All roads in the northwest portion of the plant were taped off to prevent entry from both ends.

That portion of the plant is on the peninsula surrounded by Curtis Creek. The peninsula was effectively isolated to establish the hot zone. The rest of the hazmat box was requested along with MDE and OEM. A Level A or B entry was needed to mitigate the leak, necessitating the full hazmat assignment.

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Command then set building K-10 as the staging area. The staging area was upwind and provided access through the plant road to reach the leaking truck. Once again the layout of the plant was used to create an entry\exit corridor for crews entering the hot zone. Boundaries were set for the warm and cold zone using this corridor.

Command was transferred to BC-2, and then later into the incident to BC-6, with SOC 4 moving to the hazmat group. EMS 6 was designated EMS group with M5 and M9 on scene. Safety Officer 2 served as Incident SO while SOC 2 filled the role of Tech SO. Battalion Tech 2 and 6 documented accountability and movement of units throughout the incident.

A plan for entry was created with the goal of assessing the leak, attempting to fix quickly and completing a primary search of the immediate area around the truck. T-6 and MDE 1 was recon, SQ-26 was rescue team, E-23 was the backup team at 3\4 ready with Hazmat 1 providing all necessary logistics.

Level B with SCBA, Tingley boots and Butyl gloves were chosen for PPE. The non-fuming nature of the nitric acid along with limited exposure to the small leak were deciding factors in Level A vs. B. A vacuum pump on the truck was also keeping the leak to a minimum throughout the incident. Members were equipped with pH paper during entry.

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T-6, MDE 1 made entry as a recon team with SQ-26 as rescue team on the edge of the hot zone. T-6 carried small tools and equipment to fix possible leaks. SQ-26 was on standby with FAST board and RIT bag in the event of a mayday call. E-23 was in the dress area at 3\4 ready to assist if a mayday was called.

E-35 supplied water for decon with the crew from E-57 as the decon team. Water was the right choice for decon. Nitric acid is miscible in water, so soap would not be needed to facilitate decon. M-9 was on standby as a transport unit for the entry.

The first entry was unsuccessful in stopping the leak. The gasket was destroyed and unable to be replaced. A second option, moving the truck to the plant’s waste-treatment facility, was put into play. The waste treatment facility was capable of neutralizing and processing the nitric acid into waste water.

A second entry of personnel including a truck driver were sent to cover the leaking valve with thick poly plastic and chem tape to allow the truck to be moved to the treatment area. A rescue team was on standby during this entry as well. The driver was also able to set the vacuum pump to pull vacuum during the move.

The leak was secured and the truck was moved the 1\8 of a mile on plant property to the treatment area. The incident was brought to a successful close with no injuries, and units returned to service around 0930.

Several lessons we learned on this incident. Here are the top eight.

ONE: Chemical community familiarity

The company that had the spill has been more than transparent with BCFD. The company has hosted numerous tours and training for our members, providing valuable interaction between the company and BCFD. Plant personnel on scene knew who we were and what our goals were. BCFD personnel were aware of plant accountability procedures, layout of the facility and the knowledge of the treatment facility. All of these interactions before the actual incident provided seamless cooperation when the incident does occur.

TWO: Incident command and staging

Establishing IC and staging is often overlooked. The simple act of establishing these functions sets an organized tone for the incident. Staging units until the exact location of the incident is known allows a coordinated effort to set up operations. OSHA also requires the first-arriving unit to establish command as well as the IC to have appropriate training to be the IC.

THREE: Control zones

Establishing control zones (hot, warm, cold) further builds on the incident command concept. Incoming units know exactly where the playing field is and where to set up operations. The layout of the facility provided a perfect opportunity to do this. Selected roads were cordoned off on the northwest corner of the plant isolating the operational area. The unit staging location was set up in an upwind position with access to an entry\exit corridor. The staging area also allowed an escape route should the incident go wrong and the wind changes direction. Units could simply head southeast away from the peninsula on the facility to seek refuge if needed.

FOUR: Back to the basics

Establishing command and following basic principles of hazmat response (control zones, staging, etc.) will most often lead to a successful incident. This is no different than success on the fireground. Hose lines must be advanced, ladders placed, etc. All of these basic actions should lead to success when not overlooked or bypassed.

FIVE: pH paper

Any incident involving a corrosive product demands pH paper be used. You can never have enough pH paper for assessment of the chemical and protection of personnel. Water paper should be used in conjunction with pH paper. Corrosives in transport are typically mixed with water in solution. So, using both papers will give a better assessment of the chemical concentration and the presence of water. 

SIX: PPE choice

PPE is probably the most debated subject in hazmat. The choice in this incident was Level A (vapor protection) or Level B (splash protection). Level B was chosen in this incident. Splash was the most likely exposure given the size up, nature of the chemical and size of the leak. The one thing we often overlook is suit, boot and glove compatibility.

A check of the Dupont Tychem 6000 permeation data shows >480 minute breakthrough time for nitric acid up to 90% pure. The chart also shows us that if we were dealing with fuming acids, then Tychem 6000 is no good — we would need a Tychem 10,000 Level A suit due to the fuming vapors. Also consider SCBA’s exposure to vapors. In that scenario, the straps are not rated for fuming acids.

Orange Tingley boots are a good choice and provide resistance. Although do not stand in a puddle, as that is just poor site practice. Glove choice is super important. Direct contact with the product is most likely with hands while working to fix, plug or patch a leak. Nitrile is compatible only with solvents and oils, while butyl is for corrosive products. This video shows what nitric acid can do to nitrile.

Although this incident was 68% pure nitric, any concentration can still damage nitrile or latex gloves. Always consult a permeation data chart for suits, gloves and boots to confirm your choices are the safest option available.

SEVEN: Excess taping of Level B

The choice of Level B is for splash scenarios. There is no reason to tape all the seams of the suit when donned properly. The reasoning is very simple, if you’re afraid of vapors penetrating the suit, then you should be in Level A. Tape should only be used for form fit of the suit such as around wrists to prevent rise of the sleeve, hood taped to one point on the face piece to prevent hood from being pulled back, etc.

EIGHT: Solve the problem

The goal of any hazmat response is to solve the problem. The problem in this case is a leaking truck. The nitric acid just created a hazard for us. The ultimate goal is to solve the leaking truck problem. The problem in this case was solved by off-loading it into the plant waste processing stream for neutralization. Do not lose sight of the ultimate goal. The chemical hazard involved can distract from solving the problem. Do not get tunnel vision on the chemical alone. See the big picture and solve the problem.