5.0 Recommendations

Based upon the root causes and contributing factors of this accident described above, the JCAIT provides the following recommendations to prevent accidents like this one from happening in the future:

PHAs, SOPs and Training

Before handling any substance, facilities should ensure that all chemical and process hazards and the consequences and deviations associated with the chemical and process hazards are completely understood, evaluated, documented, and appropriately addressed through preventive measures. This assessment should also include accident history, chemical incompatibilities and equipment design and integrity. One way facilities can carry out this evaluation is using a formal process hazard analysis (PHA) technique as required under the OSHA Process Safety Management Standard under 29 CFR 1910.119 or the EPA Risk Management Program Rule under 29 CFR part 68. The Center for Chemical Process Safety (CCPS) of the American Institute of Chemical Engineers (AIChE) has prepared guidance on PHA methodologies. In addition, the hazard evaluation can identify failure areas that need to be addressed by safeguards such as engineering controls, maintenance and standard operating procedures. The standard operating procedures (SOPs) should address steps for normal operations (including startups and shutdowns), anticipated deviations from normal, the consequences of such deviations and the steps to correct them, emergency conditions and steps for emergency shutdowns and placing the operation into a safe mode. After SOPs have been developed, all operating personnel, including supervisors, should be trained on the newly developed SOPs. This training must also include recognition of deviations or upset conditions and their potential consequences and corrective actions or shutdowns.

Facilities need to clarify and understand their respective responsibilities for the discovery and assessment of chemical and process hazards and process safety information in tolling or other contracting agreements. Both parties must be clear as to who will be responsible for process safety information, including chemical hazards, technology of the process, consequences of upset conditions, and identification of any previous incidents involving similar processes. The chemical and petroleum processing industries should develop basic guidelines to be used in tolling or contracting agreements the safety of which may depend on sound communication of chemical and process hazards. EPA has requested that CCPS examine whether guidance for conducting process hazards analyses and safety information sharing in tolling agreements should be developed.

Recognition and Evaluation of Abnormal Situations

The value of a thorough assessment of the chemical and process hazards using methods such as a process hazard analysis (PHA) is greater understanding of the range of possible deviations, the consequences of the deviations, and corrective actions to safely bring the process under control. Without this information, evaluation and action to correct abnormal situations when they arise may become guesswork, placing the process, the facility, the employees, the community, and the environment at risk. Facilities should routinely review their chemical and process hazards assessments to make sure new information is included, monitor accident histories and lessons learned and consider applications to their processes, and investigate deviations, no matter how minor, to prevent more serious consequences.

Proper Use of Equipment

All facilities should ensure that equipment manufacturers' recommendations are followed and that equipment is installed, operated, and maintained as designed. Equipment manufacturers typically have a wealth of information regarding the maintenance and recommended uses of equipment they manufacture. Chemical processors and toll operators should regularly contact equipment manufacturers for updated information and seek advice should equipment application, installation, operation or maintenance needs deviate or require modification from equipment manufacturers' recommendations.

Many types of industrial vessels or other equipment use mechanical seals to permit external drive of internal equipment, such as pumps, mixers, or agitators. In certain applications, mechanical seals must be liquid cooled or purged to prolong seal integrity. While regular maintenance may help prevent failure and leakage, the possibility of a malfunction always exists. Facilities should ensure that liquids used to cool or purge seals are not incompatible with materials processed in the vessels or other equipment.

OSHA/EPA Review of Highly Hazardous Chemicals List

Appendix A of OSHA's existing Process Safety Management (PSM) standard (29 CFR 1910.119) lists the toxic and reactive chemicals covered by that standard. At the time of the process safety management rulemaking, OSHA decided to include only those chemicals having the NFPA (NFPA 49) ratings of 3 or 4 for reactivity. Chemicals rated 3 or 4 are those that are capable of undergoing detonation or explosive decomposition and generating the most severe blast or shock wave. NFPA 49 assigns sodium hydrosulfite a reactivity rating of 2 and aluminum powder a reactivity rating of 1. Because of this tragic event, OSHA is considering adding additional reactive chemicals to the Appendix A chemical list.

EPA and OSHA have agreed to harmonize their lists of substances under the PSM standard and the List of Regulated Substances for the Risk Management Program in 29 CFR part 68 promulgated under section 112(r) of the Clean Air Act. EPA's current list only addresses toxic and flammable substances. As part of the upcoming 5-year review of its list, EPA will consider other hazards, including reactive chemicals.

OSHA Review of Integration of Hazard Communication (HazCom) and Hazardous Waste Operations and Emergency Response (HazWoper) Standards, with the Process Safety Management (PSM) Standard

OSHA's HazCom and HazWoper standards, combined with the PSM standard, provide an integrated approach to worker health and safety. OSHA's Hazard Communication Standard (29 CFR 1910.1200) permits the MSDS for the components of a mixture to serve as the MSDS for the mixture. Employers that rely upon an MSDS created by other entities must be aware that the MSDS for raw materials may not identify all hazards which may be encountered when mixing, blending or processing them with other materials. This may be true even if there is no reaction anticipated or apparent. Moreover, an MSDS for the final mixture may specifically address the hazards of shipping container quantities, but may not apply to the hazards of larger quantities in the processing phase.

This accident demonstrates that a review of the MSDS is an inadequate substitute for performing a process hazards analysis. As noted above, OSHA allows the collection of the MSDSs to suffice for compliance with its information collection requirements for process safety information if the MSDSs contain information to the extent that they enable employers and employees involved in operating processes to identify and understand the hazards posed by these processes. Such specific information criteria include: reactivity data, thermal and chemical stability data, and hazardous effects of inadvertent mixing of different chemicals that could foreseeably occur. A review of MSDSs alone for highly hazardous processes in lieu of a formal process hazard analysis would not meet OSHA's requirements. Industry may not clearly understand this distinction which, in this accident, may have contributed to a less than adequate hazards analyses. As a result, thermal and chemical stability as well as inadvertent mixing of chemicals were not adequately addressed in the review process.

In addition, many companies rely on MSDSs to communicate hazard and emergency response information with communities and first responders as required by EPA under the Emergency Planning and Community Right-to-Know Act. EPA and OSHA will consider whether additional guidance or outreach in the form of an Alert or other means is necessary to advise industry and first responders to make sure that MSDSs are not used beyond their intended design, to highlight areas where information can be misunderstood, and to make sure that hazards information is complete. The American National Standards Institute (ANSI) in cooperation with the Chemical Manufacturers Association (CMA) is working to revise an existing ANSI uniform MSDS format. CMA and ANSI and other industry organizations should also evaluate whether additional consensus standards or guidelines are needed for MSDS consistency and to avoid misunderstandings (e.g. the difference between chemical and process hazards) or faulty interpretations of terms (e.g. small fires or small amounts of water).

As a result of the devastating loss of five emergency responders in this event, OSHA clarified its HazWoper Standard (29 CFR 1910.120) and its Employee Emergency Plans and Fire Prevention Plans (29 CFR 1910.38) (Memorandum For All Regional Administrators; Subject: Update to HazWoper Emergency Response Guidance: Coordination with Local Fire Departments; Oct. 30, 1996). This clarification, while written for compliance officers, gives employers guidance for conducting appropriate emergency response actions as part of their emergency response plans contained in the subject standards.

Finally, as a result of this accident, OSHA issued a Hazard Bulletin about MSDSs in July 3, 1996, recommending that a process safety analysis be performed for all materials with catastrophic potential, even if not covered by the PSM standard. The analysis should include a cautious review of chemical hazards, incompatibilities and a thorough examination of all mechanical equipment. Standard operating procedures should be developed and the consequences of deviation ought to be identified. Further, employers that rely on MSDSs created by other parties must be aware that MSDSs for raw materials may not identify all hazards that might be encountered when mixing or blending with other materials. This may be true even if there is no anticipated or apparent reaction. MSDSs for the final mixture may specifically address the hazards of shipping container quantities, but may not apply to the hazards of the larger quantities needed to make the mixture.

6.0 Outcomes of OSHA/Napp Technologies Settlement

As part of the settlement between Napp Technologies and the Occupational Safety and Health Administration, Napp agreed to the following items: 1) conduct a comprehensive review of all SOP's for worker health and safety issues and compliance with worker safety and health standards; 2) conduct periodic comprehensive safety and health audits utilizing a qualified independent safety and health professional and develop action plans to abate all hazards found; 3) contract with a qualified safety professional to train Napp Safety Council members (including supervisory, technical and employee representatives) to perform their duties effectively; 4) create an SOP institutionalizing review all facility processes to identify those that should undergo a more detailed process hazard analysis; and 5) designate a responsible management official whose primary responsibility will be to oversee Napp's safety and health program, worker health and safety issues and compliance with applicable health and safety standards.

Appendix A

Results of Analysis of the Accident

Chemical Analysis Results

The results of the chemical analyses of the residues in the blender taken by EPA's Environmental Response Team revealed the presence of percentage amounts of various metals such as sodium, potassium and aluminum. This was expected, inasmuch as these metals were part of the GPA mixture. In addition, the sampling revealed the presence of large amounts of phenol and methylphenol compounds. Phenol was detected in internal ash samples and in an external crevice ash sample. To a lesser degree 2-methylphenol and 4-methylphenol were also detected in the ash samples.

Phenol and the methylphenol compounds were likely due to the insulating material remnants which were originally located in the annulus between the outer wall of the blender and the outer wall of the water-glycol jacket. Additionally, a review of the chemistry of benzaldehyde suggests that the presence of phenol and phenol compounds can be explained as follows: the aluminum in the blender had reacted with the water and sodium hydrosulfite, causing an exothermic and reducing atmosphere to form inside the blender. This resulted in the conversion of whatever benzaldehyde had been successfully introduced into the blender to a methyl hydroxy (alcohol) intermediate. This material, in the reducing environment inside the blender, was transformed to toluene, another intermediate. The toluene was in turn converted to phenol, and to a lesser degree 2-methyl phenol, and 4-methyl phenol. This reaction is a classic electrophilic aromatic substitution in which methyl groups reform preferentially onto the benzene ring in the ortho and para positions (relative to the OH group in phenol), creating phenol, and the 2- and 4-methyl phenol species respectively. This chemistry tends to eliminate the possibility that phenol, rather than benzaldehyde, had been inadvertently added to the GPA blend.

Post-Explosion Analysis of Blender

After the accident, members of the Materials Reliability Division of the National Institute of Standards and Technology (NIST) analyzed the remains of the PK-125 blender. A visual examination of the blender revealed that the outer jacket of the blender was ripped loose at the access ports and was peeled away from the stainless steel shell of the blender. The damage initially appeared to be the result of a steam explosion inside the water jacket lining. The shell sustained little gross deformation except near the bottom unloading hatch assembly area.

The bottom portion of the blender, where the discharge port was located, was severely deformed, and most of the unloading hatch assembly was missing. Much of this damage was probably caused by impact when the blender was propelled through the block wall of the blender room and/or immediately afterwards as it came to rest. The metal surrounding the discharge port was most likely very hot, which would have facilitated deformation.

The metal surrounding the access ports had striation marks resembling those typical of oxyacetylene cuts in steel. The striation marks are believed to be due to erosion that occurred when material from inside the blender was violently ejected from the loading ports at high temperature and velocity.

Further visual observations were performed by NIST personnel off-site. The surface of the stainless steel shell was examined for any visible cracks through which water (from the water jacket) could have entered the blender. With the exception of a small crack (several millimeters long) located near the discharge port, there were no visible signs of cracking. This damage is believed to have occurred during the accident and was not part of the initiating event. No localized areas of melting or heat tinting were observed.

A metal tube, approximately 400 millimeters (mm) diameter, to which the support flange is fastened on Lobe A of the blender, is welded to the stainless steel shell inside the blender. This tube had a sheet metal cover/seal on the end. Through this cover, a series of concentric pipes and shafts (vacuum tube assembly) enter the blender. The cover, which is approximately 1.5 mm thick, was severely deformed and bent in a manner suggesting that the concentric pipes were torn or blown out of the blender in the accident. Inspection of the cover inside the blender showed severe erosion damage around the opening through which the concentric pipes entered the blender. These erosion markings are similar to those found on the access ports and indicate GPA material was ejected out of this opening of the blender as well.

The interior shell near the off-load port is slightly buckled. This deformation most likely resulted from impact damage during the accident. The damage on the outside of the blender around the off-load port is more extensive. The wedge-shaped configuration of the damage was probably caused by the impact during the accident.

The most notable features on the surface of the interior were the erosion marks. These markings likely resulted from the ejection of heated material from inside the blender during the accident. The erosion was confined principally to the surfaces of the interior that form the "V" between the two lobes. The erosion occurred mostly within a region that was approximately one meter wide near the seam between the two lobes of the blender. The heaviest erosion damage is limited to a region about 200 mm wide near the centerline. The surface at the seam is not eroded. Erosion appeared on the surfaces adjacent to the seam, in the lobes, and at the top of the lobes (around ports). In both lobes, it appears that the erosion on the top side of the centerline is most severe. In addition, the erosion at the tops of Lobes A and B differ: on Lobe B the erosion is dimple-like around the access port, resembling impact damage, and erosion on Lobe A is wavy lines (flow-like) cut into the surface of the shell.

The concentric pipes and shafts of the vacuum tube assembly enter the blender (Lobe A) through the support tube. On the outside of the blender, near the end of the vacuum tube assembly, is a water-cooled graphite seal that allows the agitator shaft to turn at high speed. Examination of the seal components showed that the inboard steel ring was fractured and that the inboard graphite seal had radial fissures and circumferential gouging. The depth of the grooving was measured on a replicated surface of the inboard seal. The measurements were made on an optical microscope with a calibrated z-axis. Typically, the depth of the grooves varied from 25 to 125 microns. The width of the groove exceeded 1 mm in some regions; these grooves may have allowed water to pass through the seal over time.

Coroner's Report

This report will not detail the injuries sustained by those Napp employees who perished in the explosion. However, the physical condition of the victims provides some insight into the nature of the chemical reactions that occurred inside the PK-125 blender.

Autopsy information provided investigators by the Bergen County Medical Examiner indicates that the deceased employees suffered a combination of trauma, burns, and smoke/fumes inhalation. There were no physical signs that the victims had been subjected to the explosive force of a detonation. Rather, the physical signs indicated that what occurred was a deflagration, not a detonation. The main difference between the two is the rate of energy release and the amount of overpressure generated by the instantaneous and violent reactions of the materials involved. Had a hydrogen gas explosion occurred, it has been calculated that the entire plant, as well as a significant portion of the nearby homes, would have been destroyed in the blast. The extent of the damage, although catastrophic by any standards, was indicative of an explosion with a lower rate of energy release than that which would have been produced by hydrogen gas. This physical evidence indicates that the reactions that occurred involved the decomposition of sodium hydrosulfite and subsequent reaction products interacting with powdered aluminum.

Appendix B

Chemical Reactions

Sodium Hydrosulfite

Sodium hydrosulfite decomposes exothermically in the presence of heat, moisture, or air. Although sodium hydrosulfite is flammable, it is not explosive. Contact with small amounts of water or moist air will cause a chemical decomposition reaction that generates sufficient heat to ignite combustible materials. In one reported accident (Bretherick 1990), smoldering started when water entered a drum of sodium hydrosulfite, which then ignited when tipped over for disposal. In another case (Bretherick 1990), a batch of sodium hydrosulfite violently decomposed during drying in a graining bowl. The likely explanation was contamination with water and/or oxidant.

Exposure of sodium hydrosulfite to moisture, either from humid air or traces of water, can cause reactions that may generate enough heat to initiate thermal decomposition (NFPA 49, 1994). The reaction of sodium hydrosulfite (Na₂S₂O₄) with water can produce sodium bisulfite (NaHSO₃) and sodium thiosulfate (Na₂S₂O₄) (Equation 1). Because sodium bisulfite is an unstable solid compound (Kirk-Othmer 1983), it most likely decomposes to sodium metabisulfite (Na₂S₂O₅) and water (Equation 2). Sodium metabisulfite may then decompose to sodium sulfite (Na₂SO₃) and sulfur dioxide (SO₂) (Equation 3). Therefore, the bubbling of the GPA materials that was observed by a supervisor in the early morning of April 21 can be explained by the generation of sulfur dioxide. Because water is produced in this suggested reaction scenario, the overall reaction becomes self-sustaining; only a small amount of water is needed to initiate the exothermic reaction. As the reaction proceeds, the temperature of the blender and the GPA components would have increased.

(1) 2Na₂S₂O₄ + H₂O 2NaHSO₃ + Na₂S₂O₃

(2) 2NaHSO₃ Na₂S₂O₅ + H₂O

(3) 2Na₂S₂O₅ Na₂SO₄ + SO₂ + S

Only catalytic amounts of water are needed to make the decomposition self sustaining. In closed vessels, decomposition is likely to occur simultaneously with pressure buildup at low temperatures.

Anhydrous sodium hydrosulfite has a tendency to decompose spontaneously as in the following equation (Equation 4), forming sodium thiosulfate and sodium sulfite and releasing sulfur dioxide. Because this reaction is exothermic, the temperature of the GPA components would have continued to increase. This increase in temperature would have accelerated the decomposition and, thus, the production of sulfur dioxide, resulting in violent surface bubbling of the reaction mixture.

(4) 2Na₂S₂O₄ Na₂SO₃ + Na₂S₂O₃ + SO₂

The reaction is violent above 150 - 190C. Simple geometry influences the mode of decomposition. In 'heap' samples, insulation, and therefore self heating, is greater than in thin layers of the chemical. When a sample was heated at 15C per minute, a sudden exotherm of 47 kilojoules per mole (kJ/mol) occurred at 205C (Goodhead, 1974). Another investigator performing calorimetry experiments on sodium hydrosulfite found that there were two large exotherms preceded by a small one (Tartani and Contessa). The initial decomposition temperature was lowered by 50C (from 110C) in the presence of 0.5 to 1% water. The investigator concluded that in closed vessels, the two sets of reactions above (i.e., wet and anhydrous sodium hydrosulfite) occur simultaneously with buildup of pressure at low temperatures.

The intensifier bar rotating at a high speed, cutting through the aluminum powder and other GPA materials, may have generated frictional heat. Although tumbling the contents of the blender may have distributed some of the heat, the use of the intensifier bar may have contributed to the continuation of the sodium hydrosulfite/aluminum/water reaction.

Aluminum

Aluminum is a strongly electropositive metal and is very reactive, burning rapidly in air when strongly heated. Finely divided aluminum powder or dusts forms highly explosive mixtures in air (flash point of 645C). Ignition may be the result of heat, shock or abrasion; it may also be spontaneous due to humidity or moisture. A severe explosion occurred in a plant producing fine aluminum powder in 1983 (Bretherick 1990). Fires and explosions have occurred during grinding and polishing operations where sparks may have set off the reaction. Because of the extreme exothermic nature of its reaction with air, aluminum is used as a metal fuel. It is incorporated into explosives to increase the energy released. The use of substantial amounts of aluminum powder under high temperatures with the reduction of liberated carbon dioxide and water by the metal is used in conventional explosives enhances the energy release by up to 100%.

In a finely divided form, aluminum will react violently with boiling water to form hydrogen and aluminum hydroxide; the reaction is slow in cold water. Under ordinary circumstances, aluminum is passivated by the formation of a layer of aluminum oxide. If this protecting layer is breached, reactions consistent with its strong electropositive character may occur. In handling fires where aluminum dust is present, one is warned not to use water. In one case where aluminum dust was ignited by sparks from a grinding machine, the activation of an automatic sprinkling system and the reaction of the water with burning metal resulted in the liberation of hydrogen, which, after mixing with air, exploded (Bretherick 1990). In the Bretherick case, the primary explosion created an aluminum dust cloud which exploded forcefully, producing more dust and encompassing more aluminum dust, resulting in four tertiary explosions in all.

Because of its high affinity for oxygen, aluminum is used in metallothermic reductions of metal compounds. These reactions produce enormous amounts of heat. For example, in its reaction with chromic oxide, molten chromium (melting point 1907C) is formed. Thermite-type reactions may also occur with non-metals such as sodium hydrosulfite, sulfur dioxide, and carbon oxides. Even though sodium hydrosulfite is a reducing agent, aluminum has such an affinity for oxygen that it can extract oxygen from these compounds. A violent explosion occurred when an 8:3 molar mixture of aluminum powder and sodium sulfate was heated to 800C (Bretherick 1990). Application of sodium carbonate to red hot aluminum caused an explosion (Bretherick 1990). At high temperatures, aluminum powder also reacts violently with sulfur to form aluminum sulfide.

As examples, aluminum powder may react with sodium hydrosulfite or sulfur dioxide, produced from the decomposition of sodium hydrosulfite, according to the reactions:

4Al + 3SO₂ 2Al₂O₃ + 3S

2Al + Na₂S₂O₄ Na₂O + Al₂O₃ + 2S

The heats of reactions at 25C are -615.3 kJ/mol Al and -428.9 kJ/mol Al, respectively.⁽¹⁾

In another case, butanol attacked an aluminum gasket at 100C, liberating hydrogen (Bretherick 1990). Other alcohols would react similarly. Benzyl alcohol is produced by the reaction of benzaldehyde with sodium hydrosulfite. Therefore, conditions may exist in the reaction vessel for a similar reaction of benzyl alcohol and aluminum powder to occur.

Reactions Occurring in Mixture

The predominant reactions taking place probably were the exothermic reaction of sodium hydrosulfite with water, or with water and oxygen; the exothermic reaction of aluminum powder with water; the exothermic thermal decomposition of sodium hydrosulfite, which would have been initiated by heat from the exothermic reactions; and the exothermic oxidation of hot aluminum powder, which would have been initiated when air contacted the blender contents. The reaction products expected are consistent with the results of the chemical analysis of the site (EPA Trip Report, July 5, 1995). The source of the large phenol concentration noted in the grab samples from the blender does not seem to be a result of the reactions of the reported mixture materials, but most likely occurred at some time during initial attempts to blend the GPA components.

Calorimetry Studies

The following are the results of accelerated rate calorimetry (ARC) studies of sodium hydrosulfite and a sample approximating the composition of the GPA. The purpose of the studies was to measure the heat released from these substances in the presence of water to determine the hazard posed by these substances. Calorimetric studies obtained from the literature and a limited study conducted by the Salt Lake Technical Center confirm that the mixture was extremely hazardous. These studies confirm that small quantities of water were capable of inducing a runaway reaction at relatively low temperatures and that the presence of aluminum in the mixture provided a substantial increase in the amount of heat released during the decomposition.

A review of the literature disclosed a study entitled "Water Influence on Thermal Stability of Sodium Dithionite" (presented by V. Tartari and S. Contessa at the 5th International Symposium "Loss Prevention and Safety Promotion in the Process Industries," sponsored by the Societe de Chimie Industrielle, 28 rue Saint-Dominique, F75007, Paris. This accelerated rate calorimetry (ARC) study of the effect of water on the decomposition of sodium hydrosulfite (Na₂S₂O₄, sodium dithionite) demonstrated that addition of less than one percent of water to a sample of sodium hydrosulfite reduced the temperature at which self-heating begins from approximately 111C down to approximately 60C. Based on these results, the authors conclude that a small amount of water strongly influences the thermal stability of this material.

Additional, but limited, studies were conducted by the Salt Lake Technical Center using ARC methods to determine the effects of including aluminum in a mixture containing sodium hydrosulfite and potassium carbonate. Under these conditions, which mimic the insulated (adiabatic) conditions in the core of the mixer leading to thermal runaway, the net adiabatic temperature rise for 3.5 grams (g) of the mixture without the aluminum was 34C. For a comparable amount of the mixture including aluminum and approximating the composition of the ACR9031 mixture, the temperature excursion went off scale, and the experiment had to be scaled down. For 0.5 g of the mixture containing the aluminum, the net adiabatic temperature rise was 486C. From these data, the heats of reaction were determined. These studies demonstrated that the addition of the aluminum produced an eleven-fold increase in the amount of heat released per gram of mixture.

Appendix C

Accidents Involving Sodium Hydrosulfite and Aluminum

Sodium Hydrosulfite

The events leading to the explosion at Lodi involved the exothermic reaction of sodium hydrosulfite with water, followed by thermal decomposition of sodium hydrosulfite. A number of accidents are reported in the literature involving reaction of sodium hydrosulfite with water and generation of sulfur dioxide. Exhibit C-1 below provides short descriptions of some accidents involving fires, explosions, or reactions of sodium hydrosulfite, culled from media and other sources. This exhibit does not include reports of spills of sodium hydrosulfite where no serious consequences resulted, but evacuations were carried out as a precaution.

Sources: Newspaper reports (on-line literature search), United Kingdom's Major Hazard Incidents Data Service (MHIDAS) database, EPA's Accidental Release Information Program (ARIP) database

Aluminum Powder

The Lodi explosion likely involved the aluminum powder in the mixing vessel. Aluminum powder has been reported in a number of accidents with fires or explosions. Fine aluminum powder, like other finely powdered materials, has the potential to explode when dispersed in air. In addition to dust cloud explosions involving aluminum, there are several reports in which mixtures of aluminum powder and other chemicals exploded (e.g., an explosion of aluminum powder and glass-making chemicals in a mixing machine). A case of ignition of aluminum powder in hot weather is also reported. Exhibit C-2 presents brief descriptions of some accidents that involved fires or explosions of aluminum powder, culled from media and other sources.

Sources: Newspaper reports (on-line literature search), United Kingdom's Major Hazard Incidents Data Service (MHIDAS) database, Occupational Safety and Health Administration (OSHA) database

Aluminum Association. Recommendations for Storage and Handling of Aluminum Powders and Paste. Washington DC.

Bretherick's Handbook of Reactive Chemical Hazards, Fourth edition. pp. 20-32, 633, 1385, 1810-2. London: Butterworths 1990.

CRC Handbook of Chemistry and Physics, 75th ed. Boca Raton, FL: CRC Press. 1995

Dean, J. Lange's Handbook of Chemistry. 13th ed. New York, NY: McGraw-Hill Book Company. 1985.

Dietz, Jr., G., Skomoroski, R., Aluminum Containing Precipitating Agent for Precious Metals and Method for its use. Patent No. 4,092,154. American Chemical and Refining Co., Inc. Waterbury, CT. 1978.

Goodhead, K et al. The non-oxidative decomposition of heated sodium dithionite. J. Appl. Chem. Biotechnol. (24) pp. 71-79. 1974.

ICF, Inc., Production and Use, Accident History, Regulations/Recommendations for Transport and Handling of Sodium Hydrosulfite and Aluminum Powder. Draft October 13, 1995.

ICF, Inc., Analysis of Process Issues and Chemical Reactions Concerning the Accident at Napp Technologies, Inc. in Lodi, NJ. Draft October 16, 1995.

Kirk-Othmer 1983. Kirk-Othmer Encyclopedia of Chemical technology, 3rd ed., Vol 22, p. 153-4; Vol 2, p. 134; Vol 9, p. 562-3. New York: John Wiley and Sons, 1983.

McCowan, C. and Siewert, T., Site Assessment of a Large Blender. NIST, Boulder, CO. May 10, 1995.

McCowan, C. and Siewert, T., Inspection of P-K Blender (Napp Technologies, Lodi, NJ, and Fort Dix, NJ). NIST, July and August 1995.

McLaughlin, Dr. H., Summary of Findings to Date - Napp Technologies Incident Review. Waste Min Inc., October 4, 1995.

McLaughlin, Dr. H., Final Report - Chemical Safety Issues, Napp Technologies Incident Review. Waste Min Inc., November 2, 1995.

NFPA 1994. National Fire Protection Association, NFPA 49, Hazardous Chemicals Data. Quincy, MA: NFPA, 1994.

NFPA 1993. National Fire Protection Association, NFPA 651, Standard for the Manufacture of Aluminum Powder. Quincy, MA: NFPA, 1993.

Occupational Safety and Health Administration. Update to HazWoper Emergency Response guidance: Coordination with Local Fire Departments. Memorandum for all Regional Administrators. October 30, 1996.

Sage, G., Analysis of Napp Technologies Explosion. Syracuse Research Corp. January 13, 1997.

Appendix E