Contents

• Notice Summary 
• Applicability 
• Description 
• Events Summary 
• Significance of Events 
• Recommendations 
• Conclusions 
• References 
• Safety Notices Previously Issued 

Notice Summary

Damage to Waste Shipping Container From a Chemical Reaction at Fernald²

This notice contains lessons learned related to mixing and storing incompatible chemicals. Mixing incompatible chemicals can cause exothermic reactions or generation of hazardous gases that can result in violent explosions. Unexpected chemical reactions caused by mixing incompatible chemicals are of major concern to DOE managers and continue to occur. On May 14, 1997, a tank exploded at the Hanford Plutonium Finishing Plant as a result of chemical reaction between concentrated hydroxylamine nitrate and nitric acid. On May 22, 1997, a waste shipping container at the Fernald Environmental Management Project overpressurized, ruptured, and was damaged by heat generated from an unexpected chemical reaction between uranium, water, and magnesium. Lessons learned from these events include the following. 

• Examine potential material interactions for incompatibilities. Even if process materials are relatively non-hazardous when considered independently, some potentially dangerous interactions may occur when materials are combined. 
• Know what chemicals are being used before mixing, packaging, or storing them. Suspect or unlabeled chemicals should not be mixed. 
• Perform a process safety analysis for all chemicals with catastrophic reaction potential, even if there is no related process safety standard. 
• Assume all potentially reactive materials are still highly reactive, even if the materials have been in storage and dormant for many years. Dormant materials can still become highly reactive if exposed to the right conditions. 

Applicability

This notice applies to all DOE facilities. It should be processed as an external source of lessons learned information as described in DOE-STD-7501-95.¹ The Office of Nuclear and Facility Safety encourages DOE managers to examine the handling of chemical processes at their facilities in light of this information.

Description

Historically, activities at DOE facilities have required workers to use numerous chemicals in various missions. These chemicals range from common acids, bases, and oxidizing agents; to specialty organics, explosives, and hydrocarbon fuels; to toxic, corrosive, or flammable gases. The violent chemical reactions that can occur when incompatible chemicals are mixed can pose serious health risks to employees and result in the release of hazardous chemicals and radionuclides to the environment.

Events Summary

On May 22, 1997, at Fernald, a waste shipping container ("white metal box") over-pressurized and ruptured, releasing some of its contents. An employee walking outside a storage warehouse heard an explosion-like sound and saw a flash of light from inside the building. Two emergency response team members dressed in protective clothing and self-contained breathing apparatus entered the warehouse and saw white smoke or dust coming from the white metal box. They left the building, then heard two additional explosion-like sounds coming from the area of the box.³

Investigators determined that the white metal box contained low-level radioactive legacy waste. Some of the waste in the box contained uranium nitrates, chlorides, water, and some magnesium. Most of the magnesium was a by-product of uranium core fabrication activities that took place in 1985. Because the magnesium had been in storage for 12 years, it had formed a magnesium-oxide coating and was considered to be stable. Waste handlers had packaged the box 21 hours earlier for shipment to the Nevada Test Site. The box contained five, 55-gallon drums of waste material without lids. Additional waste material was stored between the drums as filler (see figure 1).

Figure 1. Top View of "White Metal Box" 

Investigators believe that the over-pressurization was caused by a chemical reaction among wastes placed in the box. They believe that the initial reaction was between uranium and water from the moist filler material. The reaction generated steam, heat, and hydrogen gas. As the reaction generated heat, it burned away the magnesium-oxide coating on the magnesium allowing it to react and produce additional heat and hydrogen. Although some of the steam and hydrogen gas escaped through a vent device with a capacity of 1/2 cubic foot per minute, there was sufficient build-up of hydrogen and steam pressure to cause the failure of the box fasteners. When the contents of the box contacted air, the hydrogen ignited causing additional damage to the box. (see figure 2).

Figure 2. Heat Damage to Shipping Container From Chemical Reaction² 

As an immediate corrective action, the facility manager suspended all site operations involving packaging of materials from multiple waste streams pending the results of an investigation into the event. The facility manager also directed facility personnel to perform the following programmatic corrective actions.

• Develop standards, policies, and administrative controls to evaluate the packaging process and to identify and eliminate chemical incompatibilities. 
• Develop a protocol and procedure for authorizing and evaluating compatibility when waste handlers package different waste materials in a single container. 

Lessons learned from this event include the importance of (1) not mixing incompatible materials, even if approved in a procedure; (2) evaluating packaging materials and processes (interactions); and (3) ensuring procedures govern the chemicals that can be packaged together to preclude unwanted interactions.

On May 14, 1997, a chemical explosion occurred at the Hanford Plutonium Finishing Plant (PFP) in a room where non-radioactive bulk chemicals were mixed for the now-discontinued plutonium recovery process. The reclamation plant was designed to concentrate liquid feeds, dissolve and process solid material, and perform solvent-extraction recovery of plutonium from aqueous streams. A small fire protection water line ruptured during the explosion, resulting in the release of water from the building. No one was injured, and no radioactive materials were released to the environment. The explosion caused significant localized damage to the facility.⁴

Investigators determined that the explosion occurred in a tank containing a solution of hydroxylamine nitrate and nitric acid. Based on a review of facility records, they believe the tank contained less than 20 gallons of the solution.⁵ The tank initially contained a relatively dilute solution of hydroxylamine prepared for a training exercise in 1993. Investigators determined that, because the tank was vented, evaporation caused the concentration of the reactants to increase over time. A spontaneous reaction of the two chemicals generated large quantities of steam and gas that overpressurized the tank. Investigators found no indication of a fire. They have also determined that data collected during normal shift surveillances since 1993 indicated a concentration change was occurring in the tank. They believe that facility personnel did not recognize the significance of that indicator.

On May 16, 1997, an Accident Investigation Board was formed to investigate the explosion. Some of the issues being examined by the Board include the following.

• PFP personnel did not recognize the hazard of potential autocatalytic reactions induced by concentrating dilute hydroxylamine nitrate and nitric acid. 
• PFP personnel did not perform the procedure that addressed draining the chemical solution from the tank. 

On September 20, 1990, at the Weldon Spring Site Remedial Action Site, chemicals in a plastic 55-gallon drum reacted violently and caught fire. The reaction occurred while a waste management engineer and two subcontract laborers were consolidating chemicals in 55-gallon drums for storage. The engineer had instructed one of the laborers to break up white, powdery blocks that were in a 3-gallon metal container labeled "Sodium Metal." The laborer dropped the blocks through a bung opening into the drum, which contained caustic liquids in aqueous solution. Moments later, a violent reaction began inside the drum. The engineer observed flames coming from the drum and directed both laborers to evacuate the building. As the three employees were evacuating, the contents exploded, rupturing the drum. When the drum ruptured, caustic liquid spewed over the room, spraying all three employees. Doctors at a local hospital treated them for minor chemical burns and released them.⁵

After the chemical reaction subsided, two emergency responders entered the building with self-contained breathing apparatus and personal protective equipment. They confirmed that the liquid contents of the drum were contained within a concrete-bermed area in the building. Responders identified the drum contents as 25 gallons of liquid from a deactivated oxygen canister, 20 pounds of sodium hydroxide, 1 quart of ammonium hydroxide, urine test kits, 1 quart of ammonium hydroxide (tech grade), and a portion of the white, powdery blocks from the 3-gallon container.

Investigators determined that the white, powdery blocks were hydrolyzed sodium metal. The metal was stored in an unsealed container. The waste management engineer believed that over the years of storage, the sodium metal had been exposed to moisture in the air and had completely hydrolyzed to sodium hydroxide. However, the engineer did not test a block sample to confirm this. When the laborer dropped the sodium metal into the drum, the outer layer of sodium hydroxide dissolved, exposing the sodium metal to the water and causing a violent reaction. This produced hydrogen gas, which ignited from the heat generated by the reaction.

The Occurrence Report for this event states that the underlying lesson learned is that information about work tasks, hazards, and chemicals must be readily available and easily understood by people performing the work. To be effective, instructions must be provided immediately before the task (e.g., in pre-job briefings). Support systems must be in place to help workers better understand the hazards involved in a job. These systems must be easily accessible to heighten worker awareness of job hazards and to help them when performing their tasks.

On April 19, 1995, employees at a commercial chemical blending facility in Lodi, New Jersey, were manufacturing a gold-precipitating agent when an explosion and resulting fire destroyed the facility, killing five employees. The employees were combining sodium hydrosulfite, aluminum powder, potassium carbonate, and benzaldehyde in a blender vessel. An exothermic reaction, possibly from a leaking mechanical seal on the blender vessel, produced noxious gases, prompting workers to unload the blender. During the unloading operation, an explosion propelled the vessel and its concrete supports approximately 48 feet and through two brick walls. The explosion destroyed part of the facility and caused four deaths. A fifth employee died in the resulting fire.⁶

On July 3, 1996, the Occupational Safety and Health Administration (OSHA) issued a Hazard Information Bulletin, Water-Reactive Chemicals, Hazardous Materials not Covered under 29 CFR 1910.119 as a result of their investigation into the explosion and fire at the Lodi, New Jersey, facility. The bulletin highlights the potential dangers associated with some materials not discussed in the federal process safety management regulation, 29 CFR 1910.119, Process Safety Management of Highly Hazardous Chemicals. The process safety management program required for organizations that use hazardous chemicals is defined in 29 CFR 1910.119.

OSHA personnel recommend the following program revisions in the Hazardous Information Bulletin.

• A process safety analysis should be performed for all materials with catastrophic potential, even if they are not covered by the requirements of 29 CFR 1910.119. The analysis should include a thorough review of chemical incompatibilities, chemical hazards, and malfunctions of equipment that spills or leaks one or more of the chemical reactants. 
• Facilities that rely on Material Safety Data Sheets (MSDSs) created by other organizations must be aware that the MSDSs for raw materials may not identify all hazards encountered when mixing or blending with other materials. 
• Many types of industrial vessels use mechanical seals that may be water-cooled to permit external drive of internal equipment. The possibility of malfunction and leakage of water into the vessel should be considered in any hazard analysis. 

 

Significance of Events

Chemical reactions can present significant personnel safety hazards and can damage buildings, equipment, and structures. The products of these reactions can cause the spread of radioactive contamination and hazardous materials. Equipment important to nuclear safety can be damaged or destroyed by the energy of a chemical reaction. In 1996, DOE personnel reported 350 incidents related to chemical safety.⁷ These reports included pressurizations, container ruptures, and chemical reactions as well as leaks, spills, and near-misses. Despite efforts by DOE managers to protect their workers from chemical hazards, chemical workers continue to be injured. Currently injuries from chemical hazards in DOE result in one hospitalization per month.⁸ Brookhaven National Laboratory has developed a system for categorizing the significance of these reports by severity class. The following four categories are used in this system. Class 1-Occurrences characterized by an injury or exposure requiring hospital treatment or confirmed, severe environmental effect; also occurrences that had the potential to cause these effects with all safety barriers down, except, for example, that no one was nearby to be injured or exposed, or escaped in time, or the climatic conditions were favorable.

Class 2-Occurrences characterized by minor injury (first aid) or exposure or by minor environmental damage; also occurrences that were near misses (where one additional safety barrier remained to prevent consequences) to those in Class 1.

Class 3-Potential precursors to the occurrences in class 1 or 2.

Class 4-Minor occurrences, such as leaks, spills, or releases, which may be significant in their frequency of occurrence though not their consequences.

According to the study of 1996 events by Brookhaven National Laboratory, almost 92 percent of the events are categorized as class 3 or 4. A breakdown of the safety classes is shown in figure 3. Figure 3. Classification of Chemical Safety Occurrence Reports January - December 1996⁷ 

A review of the occurrence reports from October 1995 to present shows a reduction in both significant (Class 1 and Class 2) and less-significant (Class 3 and Class 4) reports. The results of this review are shown in figure 4. It should be noted that the two United States Enrichment Corporation plants (Portsmouth and Paducah) were privatized and became NRC licensees in this time period. They did not report to the Occurrence Reporting and Processing system after January 1997. This may partially explain the reduction in DOE chemical safety occurrence reports since the beginning of 1997.

Figure 4. Chemical Safety Occurrence Reports October 1995 - May 1997⁷

The Chemical Safety Team in the Office of Worker Safety (EH-5) has noted that human factors is a major cause in chemical incidents. A review by Brookhaven National Laboratory personnel on the root causes of chemical incidents during 1996 indicates that 57 percent of the events were caused by management problems or personnel error. This data suggests that many of the events are preventable. A breakdown of the root causes is shown in figure 5.

Figure 5. Root Causes of Chemical Safety Occurrence Reports January 1996- December 1996⁷ 

Recommendations

The following measures are recommended to enhance chemical safety at DOE facilities.

• Label all chemicals. Replace deteriorating labels before information is obscured or lost. 
• Procure only the quantities of chemicals needed to accomplish the required tasks. Chemicals purchased in small packages reduce the risk of breakage, reduce storage costs, and minimize the spread of chemicals if an accident occurs. 
• Ensure that refrigeration units that store temperature-sensitive chemicals have these safety features: (1) magnetic locked doors, (2) no spark-producing controls on the inside, and (3) an alarm to warn when the temperature is too high. 
• Adhere to manufacturer precautions and recommendations for stored chemicals. 
• Examine potential chemical interactions for incompatibilities. Process materials that are relatively non-hazardous when isolated may create dangerous interactions when combined. 
• Know what chemicals are being used before mixing or packaging them. Unlabeled or suspect chemicals should not be mixed. 
• Perform a process safety analysis for all chemicals with catastrophic potential, even if there is no related process safety standard. 
• Thoroughly clean containers used to housed chemicals before placing new chemicals in them to prevent unexpected reactions. 
• Chemicals stored in shut-down process equipment may be subject to long-term changes from concentration or degradation. The condition of the chemicals should be evaluated in light of potential long-term changes, even if the shut-down system has been analyzed at the time of the shutdown. 
• All employees working with hazardous chemicals must be aware of and understand the hazards involved with their tasks. 
• Personal protective equipment worn by workers must be commensurate with the magnitude of the hazard associated with the job. Workers must be trained on the use of the equipment. 
• Procedures and programs must be in place to ensure that the mixing of different chemicals has been properly analyzed. 
• When storing chemicals in cabinets or on shelving, separate chemicals into compatible groups and store them alphabetically within compatible groups. 
• Drums used to store or transport chemicals that appear to have bulges or signs of deterioration should be vented using a custom-designed venting device under controlled conditions before they are opened. Additional information on venting devices is available in DOE/NS-0013, Safety Notice 93-1, Fire, Explosion, and High-Pressure Hazards Associated with Waste Drums and Containers.⁹ 

Chemistry experts at the Michigan State University¹⁰ have produced a chemical safety checklist that provides guidance on chemical storage, handling, and waste. This checklist can be used as basis for a proceduralized and systematic approach to chemical safety. Some of the key points in the checklist are as are as follows.

• Label all chemical containers properly and ensure the labels are securely attached. 
• Avoid storing incompatible chemicals¹¹ together. 
• Avoid storing chemicals in the open. 
• Repackage leaking containers. 
• Secure gas cylinders properly. Ensure that the cylinders are segregated, secured, and stored in a clean dry place away from the sun. 
• Label flammable storage areas and keep them free from heat and ignition sources. 
• Do not store flammable liquids in excess of National Fire Protection Association limits. 
• Label corrosive materials and store them close to the ground. 
• Label carcinogens. 
• Seal and label hazardous waste containers. 

 

Conclusions

Operating Experience, Analysis and Feedback engineers reviewed the Computerized Accident and Incident Reporting System database for accidents and injuries involving chemicals between 1990 and 1997. The results of this review indicate that during this time 838 workers were injured by chemical reactions. Of the 838 injuries, 9 were categorized as permanent disabilities. There were no reported fatalities. The total cost to DOE for equipment damage and personal injuries was approximately $9.5 million. This cost estimate does not include ancillary costs, such as lost facility production time, clean-up, investigation, and implementation of corrective actions to prevent recurrence. 

DOE O 440.1, Worker Protection Management for DOE Federal and Contractor Workers,¹¹ requires DOE site organizations to implement a written worker protection program that provides a place of employment free from recognized hazards that are causing or are likely to cause death or serious physical harm. The Order also requires facilities to implement a hazard prevention and abatement process to ensure identified hazards are managed through final abatement and control. When a serious hazard is identified, management must assess the process and take appropriate steps to prevent, abate, or mitigate the hazard.

In all four events described in this notice, chemical reactions occurred because workers were not aware of the chemical incompatibles. In September 1994, the Office of Environment, Safety and Health published DOE/EH-0396P, Chemical Safety Vulnerability Working Group Report. The report identified many vulnerabilities that have broad application across the DOE complex. Although managers at DOE facilities have taken steps to reduce these vulnerabilities and risks, accidents such as those described in this notice still occur. Managers at DOE facilities must take advantage of all resources available to them in eliminating and mitigating these risks. The resources include chemistry subject matter experts, lessons learned documents, Orders, standards, handbooks, and experiences from private industry. A document published specifically to address mixing of incompatible chemicals is DOE/EH-0296, Bulletin 93-2, Mixing of Incompatible Chemicals.¹² The bulletin describes several chemical reactions, provides information on applicable regulations and guidelines, and contains recommendations for good chemical safety.

References

¹DOE-STD-7501-95, Development of DOE Lessons Learned Programs.

² Photographs courtesy of Flour Daniel Fernald

³ OH-FN-FDF-FEMP-1997-0034, "Rapid Overpressurization of White Metal Box at Building 30."

⁴ RL--PHMC-PFP-1997-0023, "An Explosion Occurred at the Plutonium Reclamation Facility Resulting in an Emergency Response."

⁵ ORO--MK-WSSRAP-1990-0001, "Building #406 Chemical Consolidation - Violent Reaction." 

⁶ OSHA Hazard Information Bulletin, Water-Reactive Chemicals, Hazardous Materials Not Covered Under 29 CFR 1910.119.

⁷ Chemical Safety Concerns/Search of Occurrence Reporting and Processing System, John Usher, Brookhaven National Laboratory.

⁸ Lessons Learned Web Page produced by Chemical Safety Team in the Office of Worker Safety (EH-5), URL; http://tis-hq.eh.doe.gov/web/chem_safety/ 

⁹ DOE/NS-0013, Safety Notice 93-1 , Fire, Explosion, and High-Pressure Hazards Associated with Waste Drums and Containers.

¹⁰ Michigan State University, MICHIGAN STATE UNIVERSITY CHEMICAL SAFETY LABORATORY CHECKLIST 

¹¹ DOE O 440.1, Worker Protection Management for DOE Federal and Contractor Workers

¹² DOE/EH-0296, Bulletin 93-2, Mixing of Incompatible Chemicals.

• Technical Notice 94-01, "Guidelines For Valves in Tritium Service," September 1994. 
• Safety Notice 91-1, "Criticality Safety Moderator Hazards," September 1991. 
• Safety Notice 92-1, "Criticality Safety Hazards Associated With Large Vessels," February 1992. 
• Safety Notice 92-2, "Radiation Streaming at Hot Cells," August 1992. 
• Safety Notice 92-3, "Explosion Hazards of Uranium-Zirconium Alloys," August 1992. 
• Safety Notice 92-4, "Facility Logs and Records," September 1992. 
• Safety Notice 92-5, "Discharge of Fire Water Into a Critical Mass Lab," October 1992. 
• Safety Notice 92-6, "Estimated Critical Positions (ECPs)," November 1992. 
• Safety Notice 93-01, "Fire, Explosion, and High-Pressure Hazards Associated with Drums and Containers," February 1993. 
• Safety Notice 93-02, "Control of Temporary Modifications," September 1993. 
• Safety Notice 94-01, "Contamination of Emergency Diesel Generator Fuel Supplies," July 1994. 
• Safety Notice 94-02, "High-Efficiency Particulate Air Filters," August 1994. 
• Safety Notice 94-03, "Events Involving Undetected Spread of Contamination," September 1994. 
• Safety Notice 94-04, "Uninterruptible Power Supplies," November 1994. 
• Safety Notice 95-01, "Decision Analysis Techniques," August 1995. 
• Safety Notice 95-02, "Independent Verification and Self- Checking," September 1995. 
• Safety Notice 95-03, "Lessons Learned Programs," October 1995. 
• Safety Notice 95-04, "Post-Maintenance Test Programs," December 1995. 
• Safety Notice 95-05, "Department of Transportation Non- Conformances by Vendor Shippers," December 1995. 
• Safety Notice 96-01, "Chemical Spills During Loading," April 1996. 
• Safety Notice No. 96-02, "Risk-Based Analysis of Electrical Hazard," May 1996. 
• Safety Notice No. 96-03, "Compressed Gas Cylinder Safety," June 1996. 
• Safety Notice No. 96-04, "Lightning Safety," August 1996 
• Safety Notice No. 96-05, "Lockout/Tagout Programs," December 1996 
• Safety Notice No. 96-06, "Underground Utilities Detection and Excavation," December 1996. 

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This notice is one in a series of publications issued by the Office of Nuclear and Facility Safety to share nuclear safety information throughout the Department of Energy complex. For more information, contact Jim Snell, Office of Operating Experience Analysis and Feedback, Office of Nuclear and Facility Safety; U.S. Department of Energy, Washington, DC 20585, telephone (301) 903-4094. This Safety Notice should be processed as an external source of lessons-learned information as described in DOE-STD-7501-95, Development of DOE Lessons-Learned Programs.

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Safety Notices are distributed to U.S. Department of Energy Program Offices, Field Offices, and contractors who have responsibility for the operation and maintenance of nuclear and related facilities, and to other organizations involved in nuclear safety. Written requests to be added to or deleted from the distribution of Safety Notices should be sent to Christine Crow, RPI, 20251 Century Blvd., Germantown, MD 20874 or faxed to, (301) 540-2499.

The HSS Information Center maintains a file of Safety Notices and supporting information. Copies can be obtained by contacting the Info Center, (301) 903-0449, or by writing to HSS Information Center, U.S. Department of Energy, EH-72/Suite 100, CXXI/3, Germantown, MD 20874. Copies of Safety Notice are also available on the Operating Experience Analysis and feedback Home Page at http://tis.eh.doe.gov:80/web/ oeaf/lessons_learned/ons/ons.html.