The significance of API RP 2219 recommendations in the BLSR accident


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Noble Energy (formerly Samedan Oil Corporation) was a global oil and gas exploration and production (E&P) company founded in 1932. Noble Energy is permitted by the Texas Railroad Commission (RRC) to operate oil and gas wells in Texas, including the CJ Waller and Roberts leases4 in Brazoria County, the two well sites involved in this incident. The CJ Waller lease began gas production in spring 2002, and the Roberts lease began gas production in fall 2002. Noble Energy uses contractors to perform daily inspection and maintenance activities as well as to remove and transport condensate, oil, and waste liquids.

Also Noble Energy contracts with T&L Lease Services, Inc., to provide various oilfield services, including transport of waste liquids from drilling and production wells to permit waste disposal facilities. T&L Environmental Services (T&L), a subsidiary of T&L Lease Services, is Texas RRC-permitted oil and gas waste liquid hauler. The company has been in operation since spring 2001 and employs about 15 personnel. Vacuum trucks and drivers are permitted and licensed in accordance with U.S. Department of Transportation (DOT) regulations. Based on T&L regulations the trucks were not authorized to transport flammable liquids; this was confirmed by truck tank manufacturing records and manager.

The BLSR operating facility located 29 miles south of Houston and 5 miles north of Rosharon, Texas. BLSR employed 18 personnel. The facility has been in operation since the mid 1980s and in 2003 permitted by RRC6 to operate five U.S. Environmental Protection Agency (EPA) Class II waste liquid injection wells. It operates on a 24-hour/day, 7-day/week schedule. The BLSR disposal facility contains two waste liquid unloading stations – the saltwater disposal station and the mud disposal and washout pad. These stations are used to receive E&P waste liquids, including saltwater, freshwater, used drilling mud, and BS&W.

What’s happened at 4:30 pm, on January 13, 2013

At approximately 4:30 pm, on January 13, 2003 a vapor cloud deflagration and pool fire erupted at BLSR. The fire was caused by the release of hydrocarbon vapor during the unloading of basic sediment and water from two vacuum trucks into an open area collection pit. Three BLSR employees sustained serious burns; two were transported to Fort Bend County Hospital by private vehicle, and the third was transported to Danbury Hospital by Angleton EMS. Two other BLSR employees standing near the pad were not injured. Finally two BLSR employees were killed, and three were seriously burned. Also the two T&L drivers were severely burned and life-flighted to Herman Hospital; one succumbed to his injuries 46 days after the incident, one of these men died on March 2. The fire destroyed two 50-barrel (2,100-gallon) vacuum cargo tank trucks owned and operated by T&L, and heavily damaged equipment and structures in and around the BLSR unloading pad.

Accident events

Two vacuum trucks owned by T&L Environmental Services, Inc. (T&L), of Alvin, Texas, were unloading basic sediment and water (BS&W) 3 collected from two natural gas well sites owned by Noble Energy, Inc., Houston, Texas, waste liquids generated at Exploration &Production sites include saltwater and freshwater, drilling mud, and BS&W – all of which can contain some flammable hydrocarbon liquids and significant volumes of waste liquid, including potentially flammable BS&W.

In the accident day, the temperature was about 50ºF, winds were from the west, at less than 5 miles per hour ((Reference: CSB investigation report number 2003-06-I-TX September 2003)); the combination of these two measurable parameters could affected to increase the possibility of the flammable vapor releasing and moving in on the closest ignition source, if flash point of flammable liquid was less than ambient temperature. (Author)

BLSR employees were in the process of diluting drilling mud that had accumulated from earlier deliveries by adding clean water and recirculation the liquid through the hydraulic pump and back into the pad area. The two drivers exited the trucks, left the engines running, informed BLSR employees that the trucks were to be drained and rinsed out, and made their way to the drivers’ shed to complete paperwork and wait for the washout to be completed. As reported by eyewitnesses, the trucks were in position for 3 to 5 minutes when the truck engine on the north side began to violently race/rev, slowed, and then violently raced again, blowing thick black smoke from the exhaust stack.

The second (south) truck engine began the same violent racing. At this point, a deflagration occurred. The BLSR employee standing between the trucks reported that the fiberglass hood on the south truck jumped up a few inches. Another BLSR employee stated that it looked like there was a flash of lightning under the south truck. The BLSR owner and two employees in the main office heard what sounded like a muffled explosion and looked out the door toward the processing areas. They observed heavy black smoke at the concrete pad work area. One of them placed a call to 9-1-1 at 4:36 pm. Angleton Emergency Medical Services (EMS) and the Rosharon VFD arrived on scene at 4:50 pm.

The firefighters reported an intense pool fire producing a large amount of thick black smoke and very intense heat, with flames 15 feet high. The fire was brought under control at 5:35 pm. The Rosharon Volunteer Fire Department (VFD) arrived on scene within 15 minutes of the 9-1-1 call. The Angleton VFD also responded. The fire was extinguished within 50 minutes. Two Life-Flight helicopters transported two of the burn victims to a local hospital. The other three victims were transported to hospitals by private vehicle or ambulance.

Emergency responders completed their work at 10:00 pm. There was no environmental damage.

CSB investigation findings

Because of the deaths and injuries caused by this incident, the U.S.Chemical Safety and Hazard Investigation Board (CSB) launched an investigation to determine the root and contributing causes. CSB investigators arrived at the site on the morning of January 15, 2003. Over the course of the investigation, they examined physical evidence; interviewed Noble Energy, T&L, and BLSR management and hourly employees; visited other oil and gas production wells in the area; interviewed oil/gas producers and trucking company personnel; collected and tested oil/gas well production liquids; and reviewed relevant documents

The U.S. Chemical Safety and Hazard Investigation Board (CSB) found inconsistency within the industry in managing the potential flammability hazard of BS&W. In some cases, the flammability hazard is not identified or recognized, and work practices are inadequate for safe handling of the potentially flammable liquid.

The CSB investigation focused on below matters:

1) Determining the level of employer and worker awareness of flammable liquid hazards at oil/gas production wells and disposal facilities.

In a 1992 EPA study of 32 production and reclaimer BS&W samples analyzed for flammability, 17 were found to meet the DOT Class 3 flammability criteria (USEPA, 2000; p. 26). Of the BS&W samples tested by CSB and Noble Energy, and those documented by EPA, more than 64 percent were determined to meet the DOT Class 3 flammability rating.

2) Characterizing the flammability hazard of waste liquids to identify sources of flammable vapor.

CSB analysis of nine tank BS&W samples from six production wells, including one of the wells involved in the BLSR incident, resulted in flashpoints below 30ºF in eight of the samples. Also Tests commissioned by Noble Energy on BS&W samples from the CJ Waller and Roberts leases also resulted in flashpoints below 60ºF and 30ºF, respectively (For comparison, the flash point of condensate is about –36ºF, and the flashpoint of gasoline is about –45ºF.) CSB determined that a flammable vapor cloud was ignited. There are two scenarios for the source of the flammable vapor; (1) waste liquid offloaded in the disposal pad earlier in the day, (2) waste liquid delivered by one or both of the T&L vacuum trucks. CSB determined that the T&L trucks were in the process of offloading BS&W onto the concrete pad when the deflagration occurred. The flammable vapor that ignited most likely originated from this BS&W. Meanwhile it is unlikely that the flammable vapor that ignited originated from the waste liquid remaining in the pad from the earlier deliveries. Meanwhile, Physical evidence also showed that the diesel fuel in the tanks did not spill to the pad area or contribute to the pool fire behind the trucks.

3) Identifying the potential ignition source.

As discussed below, there were five possible vapor cloud ignition sources; (1) the vacuum truck diesel engine, (2) vacuum truck electrical system, (3) static electricity discharge from the offloading liquid, (4) personnel smoking, and (5) facility electrical wiring, (6) diesel engine as the most likely ignition source, (7) though high-temperature engine components and static electricity discharge cannot be ruled out. The other two possibilities were determined to be unlikely.

Based on CSB investigation result the followings are root and contributing accident causes.

1. Noble Energy management did not identify the potential flammability hazard of BS&W, properly class and describe the material, or inform employees and contractors of the hazard. The required MSDS was not provided to the vacuum truck drivers. Condensate storage tanks were not labeled with hazard information.

2. T&L management did not require the shipper to provide the vacuum truck drivers with an MSDS or other document listing the potential flammability hazard of BS&W prior to loading the truck, nor did it identify the flammability hazard of the mixture in the truck tank. Also T&L management did not implement safe work practices (such as those contained in API RP-2219, Safe Operation of Vacuum Trucks in Petroleum Service) to minimize the generation of flammable vapor and to control possible ignition sources when loading and unloading BS&W.  T&L treated all waste liquid as nonflammable, as reported by management and evidenced by the use of non-DOT certified vacuum truck tanks.  T&L did not inform the drivers that BS&W could present a significant flammability hazard, requiring special handling precautions, such as ensuring that the truck engine was upwind and far enough away to preclude contact with a flammable vapor source.

3. BLSR management did not have practices in place to recognize the potential flammability hazard of each delivered load of BS&W, nor did it implement safe handling practices when Off-loading.

  • BLSR did not review shipping papers or conduct flammability tests to determine the flammability hazard of delivered waste liquids before offloading.
  • BLSR provided no means of grounding the vacuum truck on the waste disposal pad, an important safety precaution to reduce the possibility of static discharge.
  • BLSR unloading methods did not minimize or control the generation of flammable vapor during the offloading of BS&W; there was no effort to avoid uncontrolled splashing onto the open concrete pad.
  • BLSR and T&L management were apparently not aware of API guidance.
  • BLSR relied on the vacuum truck driver to select the appropriate unloading system—saltwater disposal station, or mud disposal and washout pad—without consideration of the potential to generate significant flammable vapor and without adequate driver training on decision criteria.
  • BLSR did not provide appropriate training to employees or truck drivers on the specific hazards associated with unloading flammable liquids, methods to minimize generation of flammable vapor, and ignition sources.
  • T&L and BLSR management failed to train their employees on diesel engine over speed as an indication of the presence of a highly flammable vapor.
  • The truck drivers and at least one of the BLSR employees responded to the diesel engine malfunction by moving closer to the trucks. If they had remained where they were or moved farther away, they would not have been injured by the fire.
  • There were no emergency procedures for safe and proper response to diesel engine over speed.
  • BLSR management had no written procedures for truck unloading, operation of systems, or emergency response.

CSB recommendations that are linked to API standard

For Nobel Energy:

1. Provide documentation of the potential flammability hazard of exploration and production (E&P) waste liquids—such as a material safety data sheet (MSDS)—to all employees, contract personnel, and haulers handling waste liquids generated at well sites. Emphasize that mixing condensate with basic sediment and water (BS&W) during the removal process can significantly increase the flammability hazard. The mixture in the transport container should be treated as a flammable liquid absent positive identification to the contrary.

2. Review and revise company gauging and waste liquid removal protocols as necessary to minimize the inadvertent removal and subsequent disposal of hydrocarbon product when removing BS&W from product storage tanks.

For T&L:

1. Ensure that the written procedures for hazard identification require that all customers requesting loading and transportation of exploration and production (E&P) waste liquids provide written notification, such as a material safety data sheet (MSDS), listing the potential flammability hazard.

2. Ensure that the written procedures for safe operation of vacuum trucks incorporate applicable good practices, including techniques to minimize the possibility of exposing the diesel engine to flammable vapor, as provided in API RP-2219, Guidelines for Commercial Exploration and Production Waste Management Facilities.

3. Develop written operating procedures that incorporate best practices for unloading storage tank waste liquids; such that drivers accurately measure the quantity of liquid removed from the storage tank and minimize removal of product, such as flammable condensate.

4. Ensure that written emergency procedures address the safe response to abnormal diesel engine operation due to a flammable vapor atmosphere. Explain that the normal engine shutoff method will not function as long as flammable vapor continues to enter the intake system.

5. Conduct and document training for all personnel who handle waste liquids, using languages or formats that are clearly understood by all affected personnel.
Address the potential flammability hazard associated with E&P waste liquids, emphasizing how the withdrawal procedure is likely to increase the flammability of the vacuum truck contents through unavoidable mixing of product and basic sediment and water (BS&W).

  • Describe operating and emergency response to diesel engine over speed caused by a flammable vapor atmosphere.


1. Develop a written Waste Acceptance Plan as recommended by API Order No. G00004, Guidelines for Commercial Exploration and Production Waste Management Facilities.
Require the shipper or carrier to properly classify the flammability hazard of exploration and production (E&P) waste liquids.
Require the hauler to provide information that identifies the flammability hazard of the material before accepting the load, such as a material safety data sheet (MSDS).

2. Develop and implement written procedures and provide training to employees on the safe handling of all waste liquids delivered to the facility in accordance with API Order No. G00004, Guidelines for Commercial Exploration and Production Waste Management Facilities; and API RP-2219, Safe Operation of Vacuum Trucks in Petroleum Service.
Include requirements for proper grounding of trucks and eliminating other sources of ignition (e.g., facility electrical equipment and smoking in unloading areas).
Ensure that the material is presented in languages or formats that are clearly understood by all affected personnel.

3. Develop written procedures and provide training to employees on unloading all flammable or potentially flammable E&P waste liquids.

  • Avoid unloading flammable liquids onto an open work area, such as the mud disposal and washout pad.
  • Include alternative unloading method(s), such as using a closed piping system to minimize vapor generation.
  • Ensure that the material is presented in languages or formats that are clearly understood by all affected personnel.

4. Develop written emergency procedures and provide training to employees on response to abnormal or emergency situations, including uncontrolled flammable vapor releases that can result in a fire or explosion hazard. Ensure that the material is presented in languages or formats that are clearly understood by all affected personnel.

The minimum safety requirements of API RP 2219 – 2005

In according to API RP 2219 standard by the name of “safe operation of vacuum truck tanks in petroleum service”, the following paragraph is minimum safety requirements are the essentials and associated with BLSR accident.

  1. Vacuum truck operators shall be aware that although BS&W may consist primarily of free water, sediment and/or emulsion, it may also entrain flammable or combustible hydrocarbons. Care should be exercised to understand the potential ignition and fire hazards associated with the material being handled.  If condensate has been mixed with BS&W during the removal process, this can significantly increase the fire hazard.  From a precautionary standpoint the mixture in the transport container should be treated as a flammable liquid absent positive identification to the contrary (section 4.1.4)
  2. Unloading materials containing flammable components to open pads or pits can release vapors resulting in a fire, explosion or substance exposure hazard.(section
  3. The method chosen for off-loading should include a review of the potential hazards of the material (flammability, corrosivity and/ or toxicity) and ensure that where necessary, the procedures properly control vapors. Where flammable materials are involved, closed systems or appropriate ventilation may be necessary.  Elimination of potential ignition sources can be achieved by proper grounding, bonding, use of intrinsically safe equipment and shutting down equipment not in use (such as truck engines when gravity draining).  (section 5.7.2)
  4. Smoking, or any other sources of ignition, shall not be permitted within at least 100 ft (depending on local procedures and atmospheric conditions) of the truck, the discharge of the vacuum pump or any other vapor source (section 5.12.5)
  5. Sources of ignition include vacuum truck engine and exhaust heat, pump overheating, faulty or improper electrical devices, static electricity discharges, outside ignition sources such as smoking, motor vehicles, stationary engines, etc.(section
  6. Vacuum truck owners shall assure that vacuum truck operators are aware of the physical and chemical characteristics of flammable, combustible, toxic and corrosive materials in accordance with applicable regulations. These regulations include, but are not limited to:
    • OSHA 29 CFR 1910.120 (Hazardous Waste Operations and Emergency Response);
    • OSHA 29 CFR 1910.1200 (Hazard Communication);
    • DOT 49 CFR Parts 106-7, 171 through 180 and 397 407 & DOT 412 (Hazardous Materials Regulations). (section 4.1.1)
  7. Vacuum truck owners shall assure that vacuum truck operators are trained, knowledgeable of and comply with applicable federal, state and local regulations including, but not limited to, the following:
    • 29 CFR 1910.1000 – 1096, Subpart Z Toxic and Hazardous Substances (including Benzene at 1910.1028)
    • 29 CFR 1910.120, Hazardous Waste Operations and Emergency Response
    • 29 CFR 1910. 1200, Hazard Communications
    • 40 CFR 263, Protection of Environment
    • 40 CFR 311.1, Worker Protection Standards for Hazardous Waste Operations
    • 49 CFR,  Parts 172, 173, 178-179, 382, 383 and 390-397, Motor Carrier Safety (section 4.4)
  8. Vacuum truck owners shall prepare an emergency response plan conforming to OSHA requirements at 29 CFR 1910.38 (Employee Emergency Plans and Fire Prevention Plans), and shall train all operators in the use of that plan (4.5.2)
  9. Operators can prevent diesel engine acceleration, or “runaway,” by locating the vacuum truck upwind of vapor sources and by extending the vacuum pump discharge away from the diesel engine air intake. (section 5.6.1)
  10. Vacuum truck operators shall be aware of the hazards involved in petroleum product and associated materials transfer operations. They shall be trained in safe product transfer practices and follow company and facility safety procedures when loading and offloading vacuum trucks.  (section 5.7)
  11. MSDSs for the products being transferred shall be available to vacuum truck operators. Safe air contaminant levels (PELs and STELs) shall be identified, and a qualified person shall assess the potential for exposure. (section 5.12.1)
  12. Vacuum truck owners shall train vacuum truck operators in safe procedures for gauging and sampling flammable and combustible liquids and toxic materials in and around vacuum truck cargo tanks, source containers and receipt containers (section 5.9)
  13. The areas in which vacuum trucks are to operate must be free of hydrocarbon vapors in the flammable range, so testing shall be conducted when appropriate (testing shall be conducted before any operation is started, and if necessary, during operations, when off-loading a waste container where pockets or layers of hydrocarbon, hydrogen sulfide, water and other hazardous materials may exist). Where required by facility procedures, permits shall be issued prior to the start of any vacuum truck operations.  (section 5.2)
  14. Potential hazards include spills, flammable atmosphere within and around the vacuum truck, cargo tank or source container, hose failures and discharges of flammable vapors to the atmosphere from the vacuum truck or the source or receiving container and worker exposures to toxic vapors, liquids or solids. (section
  15. Vacuum truck owners and operators, as well as facility personnel, should be aware of the numerous potential hazards associated with vacuum truck operations in petroleum facilities. (section 5.1.1)
  16. Whenever liquids or materials are transferred into or from a tank, vessel or container (other than a surface spill), a bonding cable shall be connected from the vacuum truck to the source or receiving container. (section
  17. Vacuum truck operators shall be aware that waste products from petroleum operations may contain trace amounts of flammable or combustible liquids and gases or other hazardous materials which may cause serious injury, illness or death, if not properly handled. In addition, vacuum truck operators shall be aware that when under vacuum, even trace amount of hydrocarbons and hydrogen sulfide gas can be easily separated and create flammable and/or toxic atmospheres.(section 4.1.3)
  18. Place an appropriate portable fire extinguisher (minimum 20 lb. BC), ready for use, within close proximity of the operation. (section D.4.1.7)
  19. When transferring flammable liquids or hazardous materials, vacuum truck operators shall remain positioned between the vacuum truck and the source or receiving tank, vessel or container and within 25 ft of the vacuum truck throughout the operation. Vacuum truck operators shall monitor the transfer operation and be ready to quickly close the product valve and stop the pump in the event of a blocked line or release of material through a broken hose or connection. (section 5.12.4)
  20. All personnel shall leave the vacuum truck cab during loading and off-loading operations (section 5.12.3)
  21. Vacuum truck operators shall be trained in the use of portable fire extinguishers.  Portable fire extinguishers should be provided with the vacuum truck and also be available at the work site. (section 4.5.1)
  22. Vacuum truck operators shall know which type of personal protective equipment to use under various conditions of potential exposure or known exposure. Personal protective equipment may be required to provide body, eye and respiratory system protection.(section 4.3.1)
  23. In emergency situations such as spill response and cleanup, product safety information may be obtained from sources other than the manufacturer or shipper, including, but not limited to: Chemtrec, Department of Transportation, state and local emergency response agencies, U.S. Coast Guard, fire departments, etc.(section 4.2)
  24. Appropriate personal protective equipment, including respirators, shall be worn when a hazard assessment indicates they may be needed to prevent exposures to toxic materials or air contaminants at or above PELs, STELs or relevant TLVs (section 5.12.3)
  25. Vacuum truck cargo tanks shall be depressurized, and vapors vented to a safe area, away from personnel and sources of ignition (or to an approved vapor recovery system), before vacuum trucks are driven onto public highways. (section 5.11.2)
  26. Vacuum truck operators may provide vertical exhaust stacks, extending approximately 12 ft above the vacuum truck (or higher if necessary), to dissipate the vapors before they reach ignition sources, personnel or other potential hazards. (section 5.6.1)
  27. Vacuum truck operators may attach a length of exhaust hose to the vacuum exhaust that is sufficiently long enough to reach an area that is free from potential hazards, sources of ignition and personnel. The hose should be preferably extended 50 ft downwind of the truck and away from the source of the liquids. (section 5.6.1)
  28. The vacuum truck owner shall establish a schedule for inspecting and testing the electrical continuity of grounding and bonding cables provided with the vacuum truck (depending on the use and condition of the cables) (section 5.4 – C)
  29. Vacuum hoses constructed of conductive material or thick walled hoses with imbedded conductive wiring shall be used when transferring flammable and combustible liquids when the potential for a flammable atmosphere exists in the area of operations.(section 5.3.1)
  30. Before beginning operations, vacuum truck operators shall obtain any required permits and inspect vacuum trucks, equipment and loading/off-loading sites to assure safe operations. See Appendices C and D for inspection, maintenance and operating requirements (section 5.1.2)
  31. Before starting transfer operations, vacuum trucks should be grounded directly to the earth or bonded to another object that is inherently grounded (due to proper contact with the earth) such as a large storage tank or underground piping. (section 5.4.2)
  32. Appropriate personal protective equipment, including respirators, shall be worn when a hazard assessment indicates they may be needed to prevent exposures to toxic materials or air contaminants at or above PELs, STELs or relevant TLVs
  33. Position the vacuum truck in a safe, authorized position, upwind or crosswind from the receiving container. When transferring flammable liquids into a container located within a diked area, place the vacuum truck at least 50 ft upwind from the tank, preferably on top of or outside of the dike (section D.4.1.4)
  34. Set the vacuum truck brakes and chock the wheels (section D.4.1.5)


As a result of comparing the investigator’s findings and CSB advise; with API RP 2219 standard recommendations, we will find “What went wrong” that has leaded to the BLSR accident.
If we search the industrial accidents to find the main causes, in most of the time findings would be at least one common important issue.
This hidden reality is; employers and their employees need to pay special attention to:

A) Minimum recommended safety requirements of approved standards.
B) Providing appropriate training
C) Preparing safe working procedure


Vacuum truck: A transportable vacuum system consisting of vacuum pump, vacuum cargo tank and associated appurtenances and accessory equipment mounted on a motor vehicle (API RP 2219 section 3.25)

  • Grounding: Providing a means for electrical continuity so currents can dissipate to ground (earth). (API RP 2219 section 3.7)
  • BS&W: An abbreviation for “Basic Sediment and Water,” measured as a volume percentage from a liquid sample of the production stream.  It includes free water, sediment and emulsion. BS&W may entrain flammable or combustible hydrocarbons or oily emulsions and then may release those hydrocarbons during service handling. (API RP 2219 section 3.3)
  • Bonding: Providing electrical connections between isolated conductive parts of a system to equalize their electrical potential (voltage). (API RP 2219 section 3.2)
  • Deflagration: Propagation of a combustion zone at a velocity that is less than the speed of sound in the unreacted medium. (NFPA 69:2002 – section 3.3.8)
  • Pool fire: a pool fire resulting from a flammable liquid spill, whose boundary is defined by the radial distance at which the radiative heat flux from the pool fire has decreased to 5 kW/m2 (approximately 1600 Btu/hr-ft2)] (CCPS guideline for consequence analysis of chemical releases – 1999)


  1. CSB investigation report number 2003-06-I-TX September 2003, BLSR Operating , Ltd. Vapor cloud deflagration and fire accident
  2. API RP 2219 – 2005 “safe operation of vacuum truck in petroleum service”
  3. NFPA 69 – 2002 “ standard on explosion prevention system”
  4. CCPS guideline for consequence analysis of chemical releases – 1999

About author:
Mr. Hamed Khoshniat
Senior safety officer