Dozens of leaking hazard-ous waste containers caused a rest area on Interstate 10 in Arizona to be closed for three days recently while a cleanup contractor repackaged the damaged load of hazardous materials that were part of a tractor-trailer load. The incident occurred about 30 miles south of Phoenix. The driver transporting the containers noticed that liquid was running out of the back of his trailer. He and two rest-area maintenance employees assisting him became sick. All three were treated at a nearby hospital and released.


The vehicle was transporting a mixed load of hundreds of containers of hazardous waste from a number of California facilities, including several universities, the U.S. Coast Guard, hospitals and medical centers, laboratories, businesses, maintenance shops, a school district, and a prison. The truck was placarded DANGEROUS, FLAMMABLE and FLAMMABLE SOLID DANGEROUS WHEN WET. The 59 hazardous waste manifests for the load formed a stack 12 inches high. They listed hundreds of waste chemicals, including the following: poisonous, flammable liquids, n.o.s. (not otherwise specified); lead citrate; oxidizing substance, corrosive; mercury compounds; nitrating acid mixture; acetic acid solution; phosphorous pentoxide; hydrochloric acid; caustic alkali liquid n.o.s.; sulfuric acid; cyclohexyldiisocyanate; paint; hydrazine aqueous solution; sodium; potassium cyanide/sodium sulfide; nitrophenol; pesticide liquid, toxic, n.o.s.; acrylamide; mercury/sodium azide; arsenic/mercury; osmium tetroxide/mercuric nitrate; nitric acid; organ-ophosphorous pesticides; formaldehyde; hydrofluoric acid; and acrolein.


Since there are no county fire departments within Arizona, the Arizona Department of Public Safety (DPS) is the primary hazardous materials response agency. A state-on-scene coordinator (SOSC) re-sponded and immediately closed down and evacuated the rest area. Liquid from leaking packages in the trailer had created a puddle on the ground behind the vehicle. The Arizona Department of Environmental Quality (DEQ) also sent personnel from its emergency response unit to assist and establish an entry team to assess the situation.

The team opened the trailer`s back doors to ventilate the load and sampled the air over the spill and inside the vehicle. A combustible gas indicator did not register any readings, but a photoionization instrument showed the presence of vapors in the vicinity.

The location of the leakers could not be determined immediately. The trailer was filled with hundreds of packages ranging in size from five-gallon pails to 55-gallon drums. The latter drums were double-decked in the front of the trailer; hundreds of five-gallon pails were triple-stacked on pallets and secured with plastic shrink-wrapping; dozens of 30-gallon containers were also present.

The SOSC contacted the trucking company transporting the load by cellular telephone and immediately arranged for a cleanup contractor from Phoenix. While responders awaited their arrival, crews from the Arizona Department of Transportation brought out barricades, traffic cones, and portable electric signs and closed the rest area.

Following the arrival of the cleanup contractor`s personnel, all involved parties met for a briefing on operational procedures and the various products in the vehicle`s load.

Responders–in Level A chemical protective clothing and self-contained breathing apparatus–entered the rear of the trailer several times to remove the readily accessible small containers in an attempt to find the source of the leaks. During the first entry, one of the detection and monitoring instruments indicated the presence of 500 parts per million of carbon monoxide, which caused operations to be temporarily suspended while responders discussed the meaning of this reading.

As a precautionary measure, arrangements were quickly made to close down the east- and west-bound lanes of the adjacent interstate if it became necessary. There was no way to determine which of the hundreds of different chemicals represented on the manifests were involved in the leaks. After the SOSC consulted with outside technical experts, it was finally determined that in all probability an “interference reading” was causing a false carbon monoxide indication. There was no fire in the load and no apparent source for the carbon monoxide reading the instrument had indicated.

Multiple relief crews were on-site, and portable lighting equipment and generators were set up. As the packages of waste materials on the truck were inspected, it became apparent that at least a dozen of them were leaking their contents and that all of the hundreds of containers would have to be removed for complete inspection and decontamination of the packages and trailer. The packages and drums were taken out of the trailer and were spread on tarps that had been spread over adjacent areas of the rest area parking lot to achieve compatibility among the groups of waste materials. The resulting segregation and separation were maintained throughout the incident. It was determined through monitoring that once the packages had been segregated in the parking lot, no vapors were present. Worker protective equipment in this area was then downgraded to Level C.

Once the majority of the packages had been removed and it became clear that no further danger was imminent, responsibility for the scene was passed from the DPS to the DEQ, and a new SOSC from the DEQ took over. Under the general provisions of the State of Arizona hazardous materials emergency response plan, the DPS provides SOSCs during the “fires and explosions” phase of an incident. Once the scene is stabilized, the SOSC duty usually passes to another state agency, such as the DEQ.

The DEQ SOSC, working with emergency response representatives from the Arizona Department of Transportation, determined that the section of asphalt at the rear of the trailer had been heavily contaminated from the very outset of the incident; most of the estimated 50 gallons of spilled liquid had leaked onto this section of the pavement. The cleanup contractor was directed to remove this asphalt and treat it as hazardous waste.

As the several dozen leaking packages were discovered in the trailer, they were decontaminated, resealed, and overpacked at the scene. This operation went on for two days; about half of the packages had to be reloaded onto another transport vehicle.

The majority of the leaking packages were determined to be waste paint, although one five-gallon pail of a poison had failed and leaked. Following reloading of the last packages, the new transport vehicle was thoroughly inspected to ensure that the containers were properly blocked and braced. The parking lot was inspected to ensure that no residue remained from the spill and that the cleanup contractor received approval from the SOSC to terminate the incident.


When dozens of leaking chemicals are involved, detection instruments may prove to be unreliable and give “false positive” indications for certain chemicals because of interference from other chemicals or mixtures.

Early contact with the responsible party–in this case, the hazardous waste hauling trucking company–is essential to the swift initiation of a cleanup operation.

It is not the emergency response agency`s job to handle the cleanup of hazardous materials spills, but it must take decisive actions to secure the incident scene to protect the public from chemical exposures.

When hundreds of chemicals are involved, it could take several days to segregate, separate, and clean up the leaking packages in just one highway trailer. n

(Top) Three individuals were injured during the early phases of this incident involving a massive load of leaking hazardous waste containers discovered while the truck carrying them was stopped in an Arizona Interstate 10 rest area. (Photos by author.) (Bottom) Fifty-nine separate hazardous waste manifests listed hundreds of chemicals, gathered from facilities across the state of California, including hospitals, medical centers, laboratories, businesses, and maintenance shops.

(Left) In a two-day operation, the cleanup contractor removed all of the several hundred waste containers and discovered that more than two dozen of them were leaking their contents. (Middle) The majority of the leaking packages contained waste paint, but one five-gallon pail of poison had also failed and leaked inside the trailer, contaminating the asphalt parking lot in the rest area as well. (Right) State of Arizona representatives required that the contaminated asphalt from the parking lot be removed and disposed of as hazardous waste, since most of the estimated 50 gallons of leaking liquid landed on the pavement.

n STEPHEN L. HERMANN is hazardous materials coordinator for the Arizona Department of Public Safety and Arizona`s senior state-on-scene coordinator for hazardous materials emergency response. He is past national chairman of COHMED, the national organization of state and local hazardous materials enforcement officers, and past chairman of the Commercial Vehicle Safety Alliance Hazardous Materials Committee. Hermann has a bachelor of science degree in explosive technology and is a graduate of the U.S. Naval School Explosive Ordnance Disposal, U.S. Army Command; General Staff College; and the U.S. Army War College and is a hazardous materials specialist for his agency and a state Division of Emergency Services Hazardous Materials technical course graduate.

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