HAZ-MAT EMERGENCIES INVOLVING INTERMODAL CONTAINERS
BY GREGORY G. NOLL, C.S.P.
Intermodal freight and tank containers have gotten a standard sight in all modes of transportation. Although much like conventional varieties of freight and tank containers, they current a number of variations that may pose distinctive challenges to public security and industrial responders.
The fundamental precept of an intermodal container is to have a transport automobile that may be bodily moved on multiple mode of transportation–e.g., from ships to vehicles to railcars to fastened amenities. Intermodal containers are constructed to straightforward worldwide designs. Common designs embrace freight or field containers and transportable tank containers.
Use of intermodal containers in North America elevated in the course of the Nineteen Seventies, when the United States started for use as a “land bridge” for worldwide visitors between the Atlantic and Pacific oceans. Under this service supplied by the railroads to numerous ocean delivery corporations, a container initially loaded in Europe and en path to the Far East would journey through container ship to the U.S. East Coast, be loaded on a prepare for the journey throughout the continental United States, after which be reloaded on one other container ship on the U.S. West Coast for its final vacation spot in Asia.
In the Eighties, using intermodal containers turned extra prevalent for home transportation, notably for field containers and their cousin, the piggyback trailer. Today, greater than 4 million intermodal containers are routinely used to ship hazardous and nonhazardous supplies all through the world. This rising use of intermodal containers has additionally created new issues for public security and industrial emergency response personnel.
Freight containers are used to move hazardous and nonhazardous nonbulk packages. Configurations embrace dry vans, refrigerated items, open-top containers, and flat containers. They will be discovered on marine vessels, as containers on flatcars (COFCs) in railroad transportation, and connected to the trailer chassis throughout freeway transportation. In addition, they could even be discovered at fastened amenities, the place they’re used for short-term storage.
DESIGN AND CONSTRUCTION FEATURES
The most typical intermodal freight container is the dry van, which is used for transporting a variety of regulated and nonregulated supplies. From an emergency response perspective, they share most of the identical issues offered by vans and tractor trailers.
Key building options of intermodal freight containers embrace the next:
Container. Freight containers are generally present in two lengths–20 and 40 ft, though containers so long as 45, 48, and 56 ft can also be discovered. In some international locations, nevertheless, containers can also embrace 10- and 30-foot lengths. All ISO containers are eight ft vast. In addition to the standardized size and width, ISO additionally specifies standardized heights starting from eight to 912 ft.
The 8 2 8 2 20 intermodal freight container is used as the fundamental measuring stick in lots of statistical comparisons. This container is known as a “TEU,” that means that it’s a 20-foot equal unit. The time period “FEU”–which refers to 40-foot equal items–can also be used.
Door designs and the variety of locking assemblies on intermodal freight containers range broadly. Doors could have two-, three-, or four-latch bar assemblies. Although pretty frequent in Europe, aspect doorways are sometimes not discovered on containers in North America.
Materials of building. Freight container designs are both smooth-side containers, external-post containers, or corrugated-side containers.
Smooth-side containers are usually product of aluminum or fiberglass-reinforced plywood (FRP). Aluminum smooth-side containers are constructed of numerous panels with inside posts riveted to them, whereas the FRP containers don’t have any seen rivets or corrugations. Most of those containers are unvented. Vented smooth-side containers will be recognized by a collection of small holes alongside the highest or backside of the aspect panels.
External put up containers have numerous posts riveted to the skin of the container. They are sometimes constructed of metal or aluminum. Vented external-post containers will be recognized by the small rectangular panels often discovered close to the corners of the container sides.
The corrugated container, which has grow to be the commonest, is often constructed of metal with sides consisting of numerous welded corrugated panels. These exterior corrugations could also be a flat, sq. design or beveled with the corrugations angled or almost rounded. Most of those containers are vented; the vents seem as small rectangular panels and are close to the corners of the container`s sides or because the filler between the corrugations.
Corner castings. Supporting frames for all intermodal containers (freight containers and transportable tanks) are constructed with nook fittings generally known as nook castings. They are used to safe the container and elevate it with customary container-handling tools. Corner castings should conform to ISO Standard 1161, Specifications of Corner Fittings for Series Freight Containers. Cast-iron nook castings are prohibited.
OTHER TYPES OF FREIGHT CONTAINERS
Refrigerated containers. “Reefers” are similar to dry freight containers, however they’ve a refrigeration unit mounted on the container`s nostril or entrance finish. The refrigeration items could also be flush-mounted or uncovered. Some insulated containers can also have clip-on refrigerated items connected to the container`s entrance face in order that the container can be utilized for dry or “chill frozen” cargo. Cryogenic liquids, reminiscent of liquid nitrogen, are generally used because the refrigerant (see picture on web page 66, left).
Most refrigerated freight containers are usually not supplied with their very own energy supply. External energy supply choices embrace a ship`s energy supply, a plug-in at a hard and fast facility, a chassis-mounted generator for freeway use, a freight-car generator, a generator container, or a short lived clip-on generator. It shouldn’t be unusual to seek out 220- or 440-volt energy provide cords getting used to produce refrigerated COFCs when being transported by prepare.
The most typical design for reefers is the smooth-side container constructed of aluminum or FRP. Insulation supplies embrace polyurethane or polystyrene foam, mineral wool, and fiberglass. The insulation and refrigeration unit lower the reefer`s inner cubic capability compared with that of dry freight containers.
Flat containers. These containers are used for transporting heavy equipment, massive containers, and different particular tools not able to being transported in a field intermodal or different enclosed container. Flat containers could also be a straight platform with no bulkheads or could have a hard and fast or collapsible bulkhead.
Open-top containers. These freight containers consist of 4 sides; are usually constructed of metal or aluminum; and have an open high, which is enclosed by a canvas-like tarp. Open-top containers are used for transporting unfastened or granular supplies and objects which are too massive for totally enclosed containers.
Box container markings and placards are crucial components in (1) figuring out the hazardous supplies concerned and (2) evaluating the hazards and dangers. Container markings can embrace the next:
Reporting marks and quantity. All containers have to be marked with reporting marks and a container quantity. The initials point out possession of the tank, and the quantity identifies the precise container. These markings are usually discovered on the right-hand aspect of the tank (as you face it from both aspect) and on each ends.
Country, measurement, and sort markings. The container will show a rustic, measurement, and sort code. The nation code (two letters) signifies the tank`s nation of registry. The following 4 digits point out the ISO measurement/sort code.
The ISO nation code signifies the nation of registry for the container. However, responders ought to notice the next disclaimers. First, the nation of registration can range inside an organization`s container fleet. For instance, Evergreen Marine has containers registered within the United States and Panama. Second, the nation code could not at all times seem on the container.
The ISO measurement/sort code signifies the container`s measurement and different particular container options. The first two digits point out the container`s size and top; particular sizes are assigned particular numbers. The second pair of digits is the ISO sort code. Specific varieties of containers are assigned particular numbers, reminiscent of “00” for a closed dry van container, “10” for a vented dry-van closed container, “20” for an insulated container, “32” for a refrigerated container, “51” for open tops, and so forth.
Markings and placards. Freight containers and trailers have to be placarded in accordance with DOT and IMO rules. Which placard is used is dependent upon the hazard class, the portions of hazardous supplies being transported, and the mode of transportation.
Some particular conditions responders ought to concentrate on concerning the placarding of worldwide shipments embrace the next:
–Containers loaded with regulated commodities that exceed regulatory thresholds should show the suitable DOT placard to correspond with the commodity`s classification. Any extra placard licensed by the International Maritime Dangerous Goods Code (IMDG) also needs to be discovered [see 49 CFR 172.502(c)(1)].
–The required placard should meet the DOT placard design specs. For instance, an INFLAMMABLE placard wouldn’t be authorized in lieu of a Flammable Liquid placard, despite the fact that they’re an identical in measurement, coloration, and intent.
— It shouldn’t be unusual to seek out hazard class phrases (e.g., Flammable Liquid) written in a overseas language.
ADR/RID marking system. The European Agreement Concerning Transport of Dangerous Goods by Truck (ADR) and European Agreement Concerning Transport of Dangerous Goods by Rail (RID) are used inside Europe for the motion of transportable tank containers. These rules are in step with the IMDG necessities and are used to help emergency responders in safely figuring out the contents of a hazardous-materials transportation container or automobile. Intermodal tanks and containers shipped into the United States and North America could comprise these markings. (See sidebar on web page 65.)
HIGHWAY TRANSPORTATION–EMERGENCY RESPONSE CONCERNS
Although listed beneath freeway transportation, numerous the problems listed beneath pertain to all modes of transportation.
Emergency responders have encountered quite a few issues in coping with intermodal freight containers and tractor trailers containing hazardous and nonhazardous supplies that don’t require placarding (keep in mind the 1,000-pound rule!). Shipping paperwork could refer to those shipments as “freight of every kind” (FAK) and should not precisely replicate what’s inside the container.
Hazardous supplies shipments originating outdoors of the United States can typically create issues in clearly figuring out (1) who the shipper is and (2) who the emergency response point-of-notification is inside the United States. Although this example has improved with the DOT Emergency Response Communication rules, responders nonetheless can encounter issues in shortly accessing a educated particular person who can present correct data on what’s inside a freight container. In some cases, the U.S. point-of-contact has been a delivery dealer who has little or no information of the container`s contents. If doubtful, begin with CHEMTREC.
While the vast majority of shippers and intermodal service corporations are very respected, there are additionally those that “stay on the sting”–each operationally and financially. Haz-mat enforcement and motor service inspections have constantly discovered issues with the mechanical integrity of kit in addition to insufficient automobile and trailer upkeep (e.g., brakes, connectors, and so forth).
Improper loading procedures–which might vary from poor blocking and bracing to improper load separations between reactive chemical households and hazard lessons–typically trigger haz-mat emergencies. It shouldn’t be unusual to seek out that the final row of containers was “wedged” or pushed by a forklift into the freight container in order that the container doorways will be closed. Normal motion and vibration throughout transportation can place mechanical stress and ultimately trigger container leaks and spills. (Of course, the container that’s leaking won’t ever be behind the container!)
Intermodal carriers, notably these working in port and terminal areas, will sometimes make a number of runs throughout a one- to four-week interval. Several public security HMRTs have skilled incidents wherein the driving force had copies of the delivery papers within the truck cab for all runs in the course of the previous month. If the driving force is significantly injured or hospitalized, it could take an prolonged time period for emergency responders to collect, assessment, and decide that are the correct delivery paperwork.
The ADR/RID marking system assists European emergency responders in figuring out the contents of a hazardous-materials transportation container or automobile. Since intermodal tanks and containers shipped into the United States and North America could comprise these markings, emergency responders ought to have a fundamental understanding of this method.
Some emergency responders discuss with incidents involving intermodal freight containers as “shock packages,” since you`re by no means fairly positive what you should have till you open the doorways. In this regard, freight containers pose the identical issues as vans and tractor trailers. Remember the next security practices:
–NEVER stand in entrance of freight container doorways when opening the container. Unlock the door. Using ropes or pike poles, stand off to the aspect because the container doorways are opened. If something goes incorrect, responders will likely be off to the aspect and out of the high-hazard space. For instance, masses could shift and are available rolling out because the doorways are opened. A 55-gallon drum of water weighs roughly 465 kilos, and most corrosives and different chemical compounds weigh in extra of 500 kilos. Insulated freight containers will be very tight. Opening the container doorways and permitting the skin air to combine with the within reactive setting could end in an explosion.
–If the freight container or trailer is totally loaded, it could be extraordinarily tough to establish which container is leaking and the supply of the issue. In this case, responders should carry out “container triage”– inspecting, eradicating, and separating the containers one after the other till the leaker will be recognized.
–Forklift vehicles or different container-handling tools could also be required to carry out the container triage course of. If the container or trailer is undamaged, consider the hazards and dangers concerned in transferring the automobile to a different location the place it will likely be simpler to handle the issue (e.g., off the freeway onto an adjoining street, to an remoted space of a truckstop, to a state freeway upkeep space, and so forth).
–If a freight container has been concerned in an overturn scenario, forcible entry could also be required. When coping with noninsulated containers, the best entry factors will likely be by way of the (1) doorways (sliding vs. swinging), (2) roof, (3) partitions, and (4) ground. Remember that the partitions could have metallic or wooden sheeting on the inside and that the ground is the strongest structural aspect of the trailer.
RAILROAD OPERATIONS–EMERGENCY RESPONSE CONCERNS
Containers on flatcars (COFCs) and trailers on flatcars (TOFCs) are the 2 most typical railroad shipments discovered immediately within the United States. COFCs will be discovered on trains in numerous configurations, together with single and double stacks. The containers are connected to the flatcar by way of twist-lock attachments (i.e., nook castings), much like these used with truck chassis. Stacking cranes and container lifters are the commonest strategies of putting COFCs on trains at rail terminals.
TOFCs are usually loaded on a flatcar by a stacking crane–a spreader is connected to the container`s high corners, and the trailer is lowered onto the flatcar. Container forklifts and container lifters can be used to elevate a trailer onto a flatcar; nevertheless, not all trailers are designed to be picked up on this method, and there are particular lifting factors on the trailers. Although not as frequent, ramps (i.e., “circus ramps”) could also be out there for driving the trailer onto the flatcar. The trailer is connected to the flatcar by locking the trailer`s kingpin to a fifth wheel meeting constructed on the flatcar.
There aren’t any Federal Railroad Administration (FRA) restrictions specifying which regulated supplies could also be shipped in COFCs and TOFCs, though there could also be particular person railroad restrictions. Cargo tanks can’t be shipped as a TOFC on a flatcar.
1. Remember the fundamental clues and their precedence for figuring out intermodal containers:
markings and colours,
delivery papers and associated paperwork, and
The consist would be the main delivery doc for railroad transportation and will likely be within the possession of the prepare crew. When coping with TOFCs and COFCs, the consist will present the next:
Number of the flatcar.
Number of every trailer or container being transported on the flatcar.
Description of every hazardous materials being transported inside the trailer or flatcar. For instance, the consist description for a single UPS trailer on a flatcar could also be a number of pages lengthy, with the required delivery paper entries for every hazardous materials.
2. The newest technology of deep-well flatcars permits as much as 4 20-foot containers to be double-stacked. While these flatcars permit for the motion of extra containers, in addition they create potential issues for emergency responders, together with the next:
If the COFCs on the underside tier are placarded, the placards could also be coated by the flatcar framing and never be readily seen to emergency responders.
Depending on how the COFCs are loaded, it’s typically not potential to open the container doorways with out eradicating the container from the prepare. Upper-tier containers could also be loaded “back-to-back” and be roughly 25 ft excessive, whereas the doorways on the lower-tier containers will likely be inaccessible as a result of flatcar`s deep-well framing.
3. Flatcars containing COFCs could also be related in a collection of three to 5 automobiles, typically known as “three-packs” or “five- packs.” One central generator provides electrical energy to assist refrigerated or heated containers on these flatcars. The generator is often fueled by roughly 500 gallons of No. 1 or No. 2 diesel gasoline oil. Electrical energy is then equipped to the flatcars by 220- or 440-volt traces working inside the flatcars.
4. Haz-mat releases in COFCs and TOFCs could pose numerous challenges for emergency responders, together with the next:
Trailers with swinging doorways and loaded back-to-back will likely be tough to open with out eradicating the trailer from the flatcar. Even if the trailer has a rear rolling door, restricted house will make egress extraordinarily tough.
Even if the doorways are accessible from the rear of the flatcar, the door will likely be roughly seven ft abovegrade. A floor ladder will then be required to unlock the doorways. As already said, NEVER stand in entrance of the doorways when opening the container. Once the doorways are unlocked, ropes or pike poles must be used whereas standing off to the aspect because the container doorways are opened. If something goes incorrect, responders will likely be off to the aspect and out of the high-hazard space.
If the TOFC is concerned in a derailment or rollover scenario, the fifth wheel attachment on the flatcar could fail. Even if it doesn`t fail, the light-weight building of recent trailers could seemingly trigger the trailer roof or sidewall to fail.
If forcible entry right into a TOFC is required, the best entry factors will likely be by way of the (1) doorways, (2) roof, (3) partitions, and (4) ground. Remember that the partitions could have metallic or wooden sheeting on the inside and that the ground is the strongest structural aspect of the trailer.
* * *
An intermodal container will be bodily moved on multiple mode of transportation (e.g., from ship to truck to railcar). These containers not solely are intermodal but additionally are constructed to straightforward worldwide designs. Because intermodal containers are simply moved from one location to a different, they’re gaining acceptance because the container of alternative for transferring bulk merchandise from one nation to a different.
The most typical intermodal freight container is the dry van or “field” container. As the workhorses of the intermodal trade, they’re used for transporting a variety of regulated and nonregulated supplies. From an emergency response perspective, they current responders with the identical issues as vans and tractor trailers.
In Part 2, we are going to assessment intermodal transportable tank containers. n
Intermodal freight and tank containers have gotten more and more frequent. This container ship is being off-loaded on the Port of Baltimore. (Photos by writer.)
A 40-foot corrugated freight container is loaded on a railroad flatcar in a container on flatcar (COFC) configuration.
(Left) An instance of a smooth-side refrigerated container with clip-on liquid nitrogen refrigeration unit. (Right) A flat container with fixed-end racks transporting uranium hexafluoride.
An instance of freight container markings. The initials establish the tank`s proprietor; the quantity, the precise container.
(Top) An instance of a trailer on flatcar (TOFC). (Bottom) COFCs can current distinctive forcible entry challenges for responders.
CODES, REGULATIONS, AND STANDARDS
Intermodal containers are designed, constructed, and dealt with in accordance with numerous codes, rules, and requirements, together with United States, worldwide, and overseas home requirements. In North America, essentially the most notable embrace the next:
International Maritime Organization (IMO). Sponsored by the United Nations, IMO is the foremost maritime group for establishing security requirements for ships, their cargo, and working methods. The main IMO reference doc for the transportation of hazardous supplies and intermodal containers is the International Maritime Dangerous Goods Code (IMDG). Section 13 of the IMDG pertains to “Portable Tanks and Road Tank Vehicles” and defines the varieties of transportable tanks, design and building necessities, particular product-related options, and inspection necessities.
Although the IMDG doesn’t have the pressure of legislation, it was the primary detailed specification developed by main worldwide buying and selling international locations, and plenty of international locations have adopted it into their nationwide requirements and rules. In addition, ocean carriers have adopted IMDG because the minimal necessities for marine transportation of hazardous supplies.
U.S. Department of Transportation (DOT). Title 49 of the Code of Federal Regulations (49 CFR) covers the transportation of hazardous supplies. Parts 170 by way of 179 outline the varieties of transportable tanks, design and building necessities, particular product-related options, and inspection necessities.
Any deviations from the DOT necessities require an exemption or particular approval. If a conveyable tank container is issued an exemption, the exemption quantity will likely be stenciled on the aspect of the container (e.g., DOT-E34567).
There are some variations between the DOT and IMDG necessities, together with shell thickness calculations and reduction valve settings.
Transport Canada (TC). TC has promulgated the Transportation of Dangerous Goods Regulations, which governs the transportation and use of intermodal containers for haz-mat transportation in Canada. The respective Canadian provinces have both adopted these rules straight or have adopted related rules of their very own.
Association of American Railroads (AAR). AAR is a U.S. commerce affiliation for the railroad trade that additionally develops trade requirements and tips. All transportable tank containers accepted for transport on the railroad should meet the necessities of AAR 600, Specification for Acceptability of Tank Containers. All tank containers that meet these necessities are stenciled with “AAR 600” on both sides of the container. AAR 600 shouldn’t be legislation.
International Standards Organization (ISO). ISO requirements cowl the structural design of intermodal containers, thereby permitting for worldwide intermodal motion. ISO requirements cowl the nook casting design; dimensional design; racking and stacking necessities; and markings relative to measurement, power, and identification. Although ISO shouldn’t be legislation, it establishes the requirements ships, trailers and chassis, and railcars use for intermodal transportation necessities.
Convention for Safe Containers (CSC). CSC is a world conference primarily meant to make sure that all intermodal containers (i.e., freight, tank, and so forth) endure common inspections for structural integrity. Certain strengths, testings, and markings are included within the conference. CSC is referenced by DOT in 49 CFR Parts 450 by way of 453, and compliance is required by 49 CFR Part 173.32 b (c). n
ADR/RID MARKING SYSTEM
Also known as the “Kimmler System,” the marking system consists of two orange panels with black printing. The higher field accommodates a Hazard Identification Number; the decrease field accommodates the four-digit United Nations identification quantity.
The Hazard Identification Number (higher panel) consists of two or three figures. The first determine signifies the first hazard. In normal, the figures point out the next hazards:
2 Emission of gasoline on account of stress or chemical response
3 Flammability (vapors) and gases or self-heating liquid
4 Flammable or self-heating stable
5 Oxidizing (fireplace intensifying) impact
9 Miscellaneous harmful substance
X Reacts dangerously with water
* Doubling of a determine signifies an intensification of that specific hazard (e.g., 33).
* Where the hazard related to a substance will be adequately indicated by a single determine, the determine will likely be adopted by a zero (e.g., 30).
The second and third figures point out the secondary or tertiary hazards. In normal, the figures point out the next hazards:
1 Explosive threat
2 Gas produced in touch with water
3 Flammable threat
4 Molten state (elevated temperature)
5 Oxidizing agent
6 Toxic threat
9 Self-polymerization, threat of spontaneous violent response
X Reacts dangerously with water
23 Flammable gasoline
236 Flammable gasoline, poisonous
33 Highly flammable liquid (flash level beneath 21ºC)
X338 Highly flammable liquid, corrosive which reacts dangerously with water
40 Flammable or self-heating stable
55 Strongly oxidizing substance
559 Strongly oxidizing substance that may spontaneously result in violent response
63 Toxic or dangerous substance, flammable (flash level between 21ºC and 55ºC)
663 Highly poisonous substance, flammable (flash level not above 55ºC)
90 Miscellaneous harmful substance n
FORCIBLE ENTRY TECHNIQUES FOR INTERMODAL FREIGHT CONTAINERS
Intermodal freight containers can transport numerous varieties of regulated and nonregulated supplies. Hazardous supplies could also be present in nonbulk packages reminiscent of drums, pails, baggage, or cylinders, in addition to in bulk containers reminiscent of intermediate bulk containers (IBCs) or “totes.” If there’s proof of a leak or the inside contents have to be inspected for injury, open the field container. Obviously, the easiest way to realize entry is to open the door utilizing secure entry procedures. However, when field containers are concerned in an accident or rollover, the container will be crushed or collapsed to the purpose that its doorways have grow to be jammed.
When the container can’t be accessed by way of regular means, forcible entry is required. Unlike the smooth-side aluminum or fiberglass containers, the corrugated container will be very tough to open whether it is closely broken. The exterior partitions are comprised of corrugated welded metal panels, and the inside structural members are well-braced. In quick, corrugated metal containers are robust!
One of the quickest methods to realize entry to a broken corrugated metal container is to chop by way of the aspect or roof with an influence noticed utilizing a carbide-tip blade. However, saws can’t be used most occasions as a result of sparks could trigger a hearth or an explosion. Remember that even when the danger of explosion shouldn’t be current, saws can throw sparks into the inside house by way of the noticed minimize and ignite flamable packing supplies. As a normal rule, saws are usually not an excellent forcible entry alternative for metal containers due to the danger from fireplace. Saws could also be acceptable for chopping entry holes into the edges or roofs of containers when a hearth is concerned. For instance, when the container is loaded with Class A flamable supplies (e.g., cardboard) and a smoldering fireplace must be extinguished, you’ll be able to minimize a triangular-shaped gap and place a handline by way of the opening to smother the fireplace earlier than opening the container doorways.
Hydraulically powered rescue instruments are a sensible choice for forcible entry, as a result of they reduce the danger of fireside. Remember, nevertheless, that the rescue device`s energy plant is a possible ignition supply when flammable liquids or gases are concerned. When flammable liquids or gases are concerned, place the facility unit as far-off from the container as potential to reduce the danger of fireside or explosion. Standard hazard and threat evaluation and site-safety procedures have to be adopted (e.g., monitoring, management zones, protecting clothes, and so forth).
Field exams and sensible expertise with hydraulic rescue instruments have proven the next:
–Tools outfitted with the standard automotive suggestions are sometimes ineffective in forcing entry by way of the field doorways. The wedge-shaped automotive tip is just too massive to unfold the cargo doorways open. When used to pressure the door`s locking rod open, the wedge tip both pulls the complete rod meeting from the field or rams the door additional into the field.
–Tools outfitted with an influence cutter attachment have typically confirmed to be the best technique of forcing entry.
When forcing doorways, safe them. Case containers could also be resting in opposition to the within of the doorways. Options embrace chains or net straps with seatbelt-locking buckles. Once the lock mechanism is freed, the doorways might swing open and the load might fall on the forcible entry crew. If the doorways can’t be secured, brace or shore them up till forcible entry operations are accomplished and all personnel are away from the rear doorways. n
Entry operations into freight containers can pose bodily and chemical hazards for responders.