Planning Is First Step In Handling Ammonia Leaks From Tanks or Pipelines
THOMAS E. WRIGHT
The Hutchinson, Kan., News photo
A huge white cloud formed above the crater and moved over an exclusive suburb northwest of Hutchinson, Kan.
It was early afternoon last August 13 when an 8-inch underground pipeline carrying liquid anhydrous ammonia ruptured.
In a house-to-house search, nearly 200 residents of the Willowbrook area and nearby farms were evacuated until the next day. A sheriff’s deputy was found incapacitated in his patrol car and three other deputies required medical treatment for inhalation of ammonia fumes. An estimated 11,000 fish died in nearby Cow Creek. Vegetation in the path of the quarter-milelong cloud was blackened.
Although company crews had the damaged section of the pipeline isolated in an hour, the gas continued to escape because over 6 miles of pipe had to be hied.
Some state and local officials later expressed surprise that anhydrous ammonia was being pipelined through their state.
That escaping anhydrous ammonia can kill was demonstrated in Crete, Neb., early in the morning of February 18, 1969. A tank car ruptured in a train derailment and released 29,200 gallons of ammonia. The gas cloud that blanketed the area for some time due to a temperature inversion and no wind killed six persons and injured 53 others. Several hundred people were kept out of their homes for two days.
Members of the fire service are becoming aware of the hazardous materials being transported through or near their communities.
Anhydrous ammonia extensively used as a fertilizer, is carried by railroad tank cars and barges, as well as pipelines.
The fire service has been involved in anhydrous ammonia transportation incidents in the past and can expect to be involved in the future. Fire departments have a responsibility to learn how to handle anhydrous ammonia incidents because, as in the past, they will be on the scene long before industry employees can reach the area to provide technical assistance.
Anhydrous ammonia is classified by the Hazardous Materials Regulation Board of the United States Department of Transportation as a nonflammable compressed gas. It is pure ammonia without water (anhydrous). By weight, it is approximately 82 percent nitrogen and 18 percent hydrogen. Its chemical formula is NH3. Once released to the atmosphere, liquid anhydrous ammonia vaporizes rapidly at an expansion rate of 850 to 1. It is lighter than air so when the air is dry, the vapor will rise. When the air is damp, the vapor will combine with moisture to form a white cloud that may hug the ground.
While not considered flammable, anhydrous ammonia can burn in concentrations of 16 to 25 percent and has an ignition temperature of about 1204°F. It is normally difficult to sustain such high concentrations, but ammonia vapor should be prevented from reaching ignition source.
Ammonia boils at —28°F and freezes at — 108°F. As most fire fighters know, it is important to avoid ammonia contact with skin because the chemical can damage tissue by removing liquids from the skin.
NH3 is a colorless alkaline gas with an odor so irritating that a person will not voluntarily remain in an injurious concentration. Rescuers need to be concerned with those who may be unable to leave a contaminated area.
Comparison to propane
NH3 has certain confusing similarities and differences with propane. Both are compressed gases (stored and transported as liquids). Both have a sharp rise in vapor pressure with an increase in liquid temperature. Both are refrigerants, as they have very low boiling points. However, propane is easier to ignite and the primary concern of fire fighters in a propane pipe burst is fire.
Primary concern at an anhydrous ammonia incident should be personal injuries by contact (burns) or inhalation (respiratory damage or suffocation). Propane is heavier than air while ammonia is lighter.
While propane is insoluble in water, ammonia is one of the most water-soluble of all gases. This high solubility causes it to have an irritating action on the mucous membrane of the eyes, nose, throat and lungs. The same characteristic, according to the Fertilizer Institute, makes an abundant supply of water the best method of immediate first aid for ammonia exposure.
Injuries to humans exposed to anhydrous ammonia vapor will vary with the concentration and the duration of exposure. Industry guides warn that exposures of short duration (30 minutes) can possibly be fatal in concentrations of 2000 to 3000 parts per million. Concentrations above 5000 parts per million are considered rapidly fatal by respiratory spasm and asphyxia.
What, then, should be basic fire department actions in response to an anhydrous ammonia pipeline accident?
“A fire chief can plot pipelines on a map,” advised Terry Hayes, a safety consultant and former director of the fire prevention bureau of the Shreveport, La., Fire Department. “He can know the companies responsible for them. He should call on company officials and request information as to what aid he can expect, how long it would take to bleed down a line, what treatment should be used. He will probably find the company cooperative.”
DOT regulations require pipeline markers at each public road crossing, each railroad crossing and in sufficient numbers along the line. However, such line markers are not required in heavily developed urban areas where such placement would be impracticable and the local government has substructure records.
Hayes suggested that volunteer fire departments devote special attention to locating pipelines as rural areas are more likely to contain underground transmission systems.
“If they don’t know it’s out there and go charging into a situation like anhydrous ammonia, they’re going to suffer and the community is going to suffer,” Hayes warned.
How to handle incidents
The Fertilizer Institute recommends these steps for handling anhydrous ammonia accidents:
- Approach the scene from upwind.
- Evacuate persons who are downwind from a major discharge.
- Administer first aid immediately.
- Keep everyone, including spectators, upwind.
- Apply a fog stream to the leak to reduce the amount of vapor released to the atmosphere or put the fog stream in the vapor cloud to help dissipate it.
- Use self-contained breathing apparatus.
- Full protective clothing made of rubber or other material impervious to ammonia must be worn.
Haves stressed that “full protective clothing” means the best turnout gear available plus complete protection for any exposed skin, eyes and the respiratory system. This means taping sleeves around gloves and bunker pant legs around boots. It means a tight waistband to keep vapors from getting under clothing. It means covered neck and ears. It means a tight mask.
Water for burns
Water and lots of it is considered the best first-aid treatment for ammonia burns. Time is important. If skin contact is extensive and showers or water tanks are nearby, get the victims into them. In any case, the exposed body area should be flushed for 15 minutes and the casualty taken to a physician. No salves or ointments should he applied to ammonia burns for at least 24 hours.
Contaminated clothing should be removed under running water if possible. If clothing has been frozen to the skin, it must be thawed with water.
Ammonia inhalation is the other first aid problem. Artificial respiration may be required for severe exposures. Oxygen has been found helpful. The victim should be kept warm.
CHEMTREC (Chemical Transportation Emergency Center) may be phoned, 800-424-9300, toll-free, at any hour for assistance in dealing with chemical emergencies, including anhydrous ammonia.
The DOT suggests the prevention of ammonia runoff to a stream or body of drinking water by “diking waste for later disposal.” Runoff to storm sewers or sanitary systems is acceptable if the area can be deluged with water. The Coast Guard or the Environmental Protection Agency should be advised, along with state and local health officials, when there is a possibility of anhydrous ammonia getting into water.
The Hazardous Materials Regulation Board warns against putting water on a liquid ammonia spill or touching the pool. Water should be directed to the discharge point while efforts are made to close valves.
The two anhydrous ammonia pipeline systems in the United States are operated by Mid-America Pipeline Company (MAPCO) and Gulf Central Pipeline Company, both headquartered in Tulsa, Ok la. The MAPCO line runs from the Texas Panhandle through Oklahoma, Kansas and Nebraska into Iowa. The Gulf Central route begins in the Gulf Coast area of Louisiana and extends through Arkansas, Missouri, Iowa, eastern Nebraska, Illinois and Indiana. A proposed Canadian line would extend from Alberta to Iowa, crossing Montana, North Dakota, South Dakota and Minnesota.
Pipeline safety cited
Pipelines are the safest method of transporting ammonia, considering the possibilities of train derailments and truck wrecks, according to Dr. Robert J. Robel, an environmental scientist and chairman of the Kansas Governor’s Advisory Council on Energy and Natural Resources. He added that pipelining produces no loss of soil and “is esthetically pleasing.”
Liquid pipeline carriers claim a safety record of about .007 deaths per billion ton miles, “unmatched by any other transportation mode.” An industry accident analysis indicated that 90 percent of pipeline accidents are related to the pipe itself and are caused by “third-party digging equipment” puncturing the line or defects resulting from corrosion, material flaws or bad workmanship.
Pipeline companies aim an awareness program at excavators, landowners, public safety agencies and others to provide information about pipeline locations, identification, products moved and telephone numbers for emergency contacts.
Much of a modern pipeline is operated remotely but maintained by crews stationed along the line who also are available for emergency repairs. The MAPCO ammonia system, for example, is monitored by a central control center in Tulsa. Telemetered information on abrupt changes in pressure and flow can signal a large leak and the control center operator has authority to immediately shut down the pipeline system.
Smaller leaks are observed by periodic aerial and ground patrols, reports from landowners and measurement of differences between inputs and outputs.
The purpose of the anhydrous ammonia pipeline, as explained by Gilbert Y. Rohleder, MAPCO vice president, is to move ammonia plant production “to delivery terminals and large central storage in the market area at a uniform daily production rate.” Railroad tank cars and tank trucks are loaded at terminals to service dealers’ storage tanks.
Rohleder said an ammonia pipeline would normally be at least 116 inches deep in fields. 48 inches below the bottom of the ditch at railroads and highways and under at least 48 inches of cover in water crossings. He said the system is kept full of liquid anhydrous ammonia to reduce pipeline transit time to zero.
Common carrier pipelines are monitored by the Interstate Commerce Commission in tariff matters.
The Office of Pipeline Safety of the DOT has authority over pipelines transporting hazardous liquids. The DOT Office of Hazardous Materials oversees shipment of ammonia hy rail and truck. The Coast Guard is responsible for transportation by water. The National Transportation Safety Board investigates accidents in all forms of transportation, including pipelines.
Intrastate transportation and usage of ammonia comes under the United States Department of Labor’s Occupational Safety and Health Administration and various states have rules covering farm storage and use of the chemical.
A spokesman for The Fertilizer Institute, Donald N. Collins, noted that “any number of regulations will not ensure safety.” He cited the industry’s recognition of the need for precautions in operations involving ammonia.
“Such industry concern and action has resulted in the fact that accidents in ammonia handling in the United States are extremely few. . .especially in light of the large quantities of this material used.”
A wide-ranging study was conducted last year for the Office of Pipeline Safety to obtain data concerning the “design, construction, operation, and maintenance of pipeline systems transporting highly volatile, toxic, or corrosive liquids.. .
The Office of Pipeline Safety will use the study results, said Director .Joseph C. Caldwell, “to propose additional regulations in areas where a need is found for additional protection for the public.”