U.S. CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD

INVESTIGATION REPORT

REPORT NO. 2003-06-I-TX

SEPTEMBER 2003

(3 Killed, 4 Injured)

BLSR OPERATING, LTD.

ROSHARON, TEXAS

JANUARY 13, 2003

KEY ISSUES

RECOGNIZING FLAMMABILITY HAZARDS OF

EXPLORATION AND PRODUCTION

WASTE LIQUIDS

SAFE HANDLING OF FLAMMABLE LIQUIDS

VAPOR CLOUD DEFLAGRATION AND FIRE
2
3

Abstract

Information about available

publications may be obtained by

contacting:

U.S. Chemical Safety and Hazard

Investigation Board

Office of Prevention, Outreach,

and Policy

2175 K Street NW, Suite 400

Washington, DC 20037-1848

(202) 261-7600

CSB publications may be

purchased from:

National Technical

Information Service

5285 Port Royal Road

Springfield, VA 22161-0002

(800) 553-NTIS or

(703) 487-4600

Email: info@ntis.fedworld.gov

For international orders, see:

www.ntis.gov/support/

cooperat.htm.

For this report, refer to NTIS

number PB2004-100007.

.

Salus Populi Est Lex Suprema

People’s Safety is the Highest Law

This investigation report examines a vapor cloud deflagration and

fire that occurred on January 13, 2003, at BLSR Operating,

Ltd., near Rosharon, Texas. 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. This

report identifies the root and contributing causes of the incident. It

makes recommendations on recognizing the flammability hazards of

exploration and production waste liquids, and on safely handling

flammable liquids.

The U.S. Chemical Safety and Hazard Investigation Board (CSB) is

an independent Federal agency whose mission is to ensure the safety

of workers, the public, and the environment by investigating and

preventing chemical incidents. CSB is a scientific investigative organization; it is not an enforcement or regulatory body. Established by

the Clean Air Act Amendments of 1990, CSB is responsible for

determining the root and contributing causes of accidents, issuing

safety recommendations, studying chemical safety issues, and

evaluating the effectiveness of other government agencies involved

in chemical safety.

No part of the conclusions, findings, or recommendations of CSB

relating to any chemical incident may be admitted as evidence or

used in any action or suit for damages arising out of any matter

mentioned in an investigation report (see 42 U.S.C. § 7412

[r][6][G]). CSB makes public its actions and decisions through

investigation reports, summary reports, safety bulletins, safety recommendations, case studies, incident digests, special technical publications, and statistical reviews. More information about CSB may be

found at www.csb.gov.
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Contents

EXECUTIVE SUMMARY............................................................ 11

1.0 INTRODUCTION ........................................................... 13

1.1 Background ........................................................................ 13

1.2 Investigative Process ........................................................... 14

1.3 Companies Involved .......................................................... 14

1.3.1 Noble Energy, Inc. .............................................. 14

1.3.2 T&L Environmental Services, Inc. ....................... 14

1.3.3 BLSR Operating, Ltd. ........................................... 15

1.4 BS&W Handling ............................................................... 16

1.4.1 Generation of BS&W .......................................... 16

1.4.2 Removal and Transport ........................................ 17

1.5 BS&W Disposal ................................................................. 19

1.5.1 Saltwater Disposal Station .................................... 20

1.5.2 Mud Disposal and Washout Pad ......................... 20

1.5.3 Other Facility Equipment ..................................... 23

1.5.4 Operating Procedures and Worker Training ........ 24

2.0 DESCRIPTION OF INCIDENT ...................................... 25

2.1 The Incident ...................................................................... 25

2.2 Emergency Response ......................................................... 26

2.3 Property Damage ................................................................ 27

3.0 INCIDENT ANALYSIS ..................................................... 29

3.1 Hazard Recognition ........................................................... 29

3.1.1 Flammability Hazard of Production Liquids ......... 31

3.1.2 Flammability Hazard of Waste Liquids ................ 33

3.2 Safe Handling of BS&W ................................................... 34

3.2.1 Waste Liquid Deliveries Prior to Incident ............. 35

3.2.2 Waste Liquid Delivered by T&L Trucks............... 36

3.2.3 Storage Tank Draining Procedures ....................... 37

3.3 Ignition Sources.................................................................. 40

3.3.1 Vacuum Truck Diesel Engine................................ 40

3.3.2 Vacuum Truck Electrical System ........................... 44

3.3.3 Static Electricity From Offloading Liquid ............. 44

3.3.4 Personnel Smoking ............................................... 45

3.3.5 Facility Electrical Wiring ...................................... 45

4.0 INDUSTRY ASSOCIATIONS .......................................... 47

4.1 American Petroleum Institute .............................................. 47

4.2 National Tank Truck Carriers, Inc...................................... 47
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Contents (cont’d)

5.0 REGULATORY ANALYSIS .............................................. 49

5.1 U.S. Environmental Protection Agency............................. 49

5.2 Texas Railroad Commission .............................................. 49

5.3 Occupational Safety and Health Administration ............... 51

5.4 U.S. Department of Transportation .................................. 52

6.0 ROOT AND CONTRIBUTING CAUSES ..................... 53

6.1 Root Causes...................................................................... 53

6.2 Contributing Causes ......................................................... 53

7.0 RECOMMENDATIONS................................................. 55

8.0 REFERENCES................................................................. 61

APPENDIX A: BS&W Hazard Summary Table ........................ 63

APPENDIX B: Logic Diagram..................................................... 65
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Figures and Tables

1 Typical Vacuum Truck Used to Haul

Oilfield Waste Liquids................................................... 15

2 CJ Waller Lease Water and Condensate

Storage Tanks ............................................................... 16

3 Condensate Tank Drain Manifold and Valves .............. 17

4 Typical Vacuum Truck Tank Sight Gauge ..................... 18

5 BLSR Facility Layout ..................................................... 19

6 Pad Area Hydraulic Sump Pumps and

Wooden Stop Beam ..................................................... 21

7 Layout of Mud Disposal and Washout Pad,

With T&L Vacuum Trucks Positioned as

on January 13, 2003.................................................... 23

8 North Side Truck Manway Bolts Partially Removed ..... 25

9 Truck Tank Drain Valves in Closed Position .................. 27

10 Mud Disposal and Washout Pad, Showing

Burned Trucks and Damaged Canopy .......................... 28

11 Unlabeled Flammable Condensate Storage

Tanks, CJ Waller Lease ................................................ 31

12 Condensate Storage Tank Located at Gas

Regulator Station .......................................................... 32

13 Gauge Hatch and Tank “Thief” Showing

13 Inches of BS&W Below Condensate..................... 33

14 Vertical Spacing of Storage Tank Nozzles..................... 38

15 South Truck Diesel Engine Turbocharger

Discharge Elbow .......................................................... 42

16 Diesel Engine Exhaust and Intake System ..................... 42

17 Bent Exhaust Valve Pushtube, South Truck

Diesel Engine Combustion Chamber #2 ..................... 43

18 Truck-Mounted Ground Cable Recoil Device ............. 45

19 Remains of Motor Control Switch Panel ...................... 46

Figures
8

Figures and Tables (cont’d)

Tables

1 Flammable Liquid Flashpoints .......................................... 30

2 BLSR Delivery Summary for January 13, 2003 ................ 35
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Acronyms and Abbreviations

AIT Autoignition temperature

API American Petroleum Institute

BLSR BLSR Operating, Ltd.

BS&W Basic sediment and water

CFR Code of Federal Regulations

CSB U.S. Chemical Safety and Hazard Investigation

Board

DOT U.S. Department of Transportation

E&P Exploration and production

EMS Emergency medical services

EPA U.S. Environmental Protection Agency

oF Degrees Fahrenheit

FM Farm-to-market

FR Federal Register

LFL Lower flammability limit

MSDS Material safety data sheet

mJ MilliJoule

NFPA National Fire Protection Association

NTTC National Tank Truck Carriers, Inc.

OSHA Occupational Safety and Health Administration

PVC Polyvinyl chloride

RCRA Resource Conservation and Recovery Act

RP Recommended practice (API)

rpm Revolutions per minute

RRC Texas Railroad Commission

T&L T&L Environmental Services, Inc.

TCLP Toxicity characteristic leaching procedure

UFL Upper flammability limit

VFD Volunteer fire department
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Executive Summary

On January 13, 2003, at approximately 4:30 pm, a vapor cloud

deflagration and pool fire erupted at the BLSR Operating, Ltd.

(BLSR), facility located 5 miles north of Rosharon, Texas. Two BLSR

employees were killed, and three were seriously burned. Two T&L

Environmental Services, Inc. (T&L), truck drivers, who had just

delivered gas condensate storage tank basic sediment and water

(BS&W) to BLSR, were seriously burned; one of these men died on

March 2.

The fire was caused by the release of hydrocarbon vapor during the

unloading of BS&W from two vacuum trucks into an open area

collection pit. BS&W is an oil/gas exploration and production (E&P)

waste liquid. The fire destroyed two 50-barrel (2,100-gallon)

vacuum trucks and seriously damaged waste liquid offloading equipment and structures at BLSR. One of the vacuum truck diesel

engines was the most likely source of ignition.

The oil and gas industry disposes of many thousands of barrels of

E&P waste liquids annually, including potentially flammable BS&W.

Although these liquids are exempt from Resource Conservation and

Recovery Act hazardous waste management regulations, they are not

exempt from hazard communication regulations of the Occupational

Safety and Health Administration (OSHA) or hazardous material

transportation regulations of the U.S. Department of Transportation

(DOT). Furthermore, E&P waste liquids can have flammability

characteristics that meet the definition of a flammable liquid in both

OSHA and DOT regulations, thus posing a significant physical

hazard to personnel.

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 incident investigation revealed the following root causes:

 Noble Energy, Inc., the shipper, failed to identify the flammability hazard of BS&W generated at its gas well production

facility, and also failed to communicate the hazard to employees

and contractors who were required to handle the flammable

liquid.

On January 13, 2003 . . .

a vapor cloud deflagration and

pool fire erupted at the

BLSR Operating facility . . .

The fire was caused by the release

of hydrocarbon vapor during

the unloading of BS&W from

two vacuum trucks into

an open area collection pit.

CSB found inconsistency within the

industry in managing the potential

flammability hazard of BS&W.

Noble Energy, the shipper, failed to

identify the flammability hazard of

BS&W generated at its gas well

production facility . . .
12

 T&L management did not require Noble Energy to provide

vacuum truck drivers with a material safety data sheet or other

document listing the potential flammability hazard of BS&W,

nor did it identify the flammability hazard of the mixture in the

vacuum truck tank.

 BLSR management did not have effective hazard communication practices in place to recognize the potential flammability

hazard of each shipment of BS&W, nor did it implement safe

handling practices when offloading flammable liquid onto the

mud disposal and washout pad area.

Contributing causes of the incident are summarized below:

 T&L employees did not understand the potential flammability

hazard of BS&W in the product storage tank, nor did they

understand that inadvertent mixing of hydrocarbon product

with waste liquid when filling the vacuum truck tank most likely

increased the flammability hazard of the truck contents.

 T&L and BLSR management did not implement safe work

practices to minimize the generation of flammable vapor and to

control ignition sources.

 Neither T&L nor BLSR management and employees recognized that the truck diesel engines presented multiple vapor

ignition sources.

CSB makes recommendations to Noble Energy, Inc.; T&L Environmental Services, Inc.; BLSR Operating, Ltd.; U.S. Department of

Transportation; Occupational Safety and Health Administration;

Texas Railroad Commission; American Petroleum Institute; and

National Tank Truck Carriers, Inc.

T&L [Environmental Services] . . .

did not require Noble Energy to

provide vacuum truck drivers

with a . . . document listing the

potential flammability hazard of

BS&W, nor did it identify the

flammability hazard of the mixture

in the vacuum truck tank.

BLSR . . . did not . . . implement safe

handling practices when offloading

flammable liquid . . .
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1.0 Introduction

1.1 Background

At approximately 4:30 pm on January 13, 2003, a vapor cloud

deflagration1 and pool fire2 erupted at the BLSR Operating,

Ltd. (BLSR), facility located in Brazoria County, Texas, 29 miles south

of Houston and 5 miles north of Rosharon. 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.

Two BLSR employees were killed, and three were seriously burned.

One of the two T&L truck drivers who were seriously burned 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.

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 LifeFlight helicopters transported two of the burn victims to a local

hospital. The other three victims were transported to hospitals by

private vehicle or ambulance.

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, and to

issue recommendations in an effort to prevent similar occurrences.

The CSB investigation focused on:

 Determining the level of employer and worker awareness of

flammable liquid hazards at oil/gas production wells and

disposal facilities.

 Characterizing the flammability hazard of waste liquids to

identify sources of flammable vapor.

 Identifying the potential ignition source.

1

A deflagration is an ignition and rapid burning of an unconfined flammable vapor cloud

at less than the speed of sound. Although it produces a pressure wave, the energy is

less than that produced by a confined vapor cloud explosion.

2

A pool fire is a flame over a puddle or pool of liquid fuel. The heat released by

combustion of the vapor fuel supplies the energy to vaporize the liquid.

3

The Texas Railroad Commission (RRC) defines “basic sediment and water” as a

mixture of crude oil or condensate, water, and other substances that collects at the

bottom of crude or condensate storage tanks.
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1.2 Investigative

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.

1.3 Companies

1.3.1 Noble Energy, Inc.

Noble Energy (formerly Samedan Oil Corporation) is a global oil and

gas exploration and production (E&P) company founded in 1932.

Average production in 2002 from wells located in eight states and the

Gulf of Mexico was 327,451,000 cubic feet of gas per day and

18,110 barrels of oil per day, as reported on Noble Energy Form

10-K. 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.

1.3.2 T&L Environmental Services, Inc.

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 permitted waste disposal facilities.

T&L Environmental Services (T&L), a subsidiary of T&L Lease

4

A “lease” is a area that produces oil, gas, or oil and gas; or any group of contiguous

wells producing oil, gas, or oil and gas of any number operated as a producing unit.

Involved

Process
15

5

The Texas RRC term “hauler” is the same as the DOT term “carrier.” The hauler

transports commodities on public highways in accordance with DOT regulations.

6

Texas RRC Project #F14563, August 21, 1995.

7

40 CFR 146.5(b).

Services, is a Texas RRC-permitted oil and gas waste liquid hauler.5

The company has been in operation since spring 2001 and employs

about 15 personnel. T&L Lease Services subcontracted waste

hauling to T&L Environmental Services.

Vacuum trucks and drivers are permitted and licensed in accordance

with U.S. Department of Transportation (DOT) regulations.

Figure 1 shows a typical 50-barrel vacuum truck, similar to the two

that were destroyed in the January 13 incident. T&L management

stated that the trucks were not authorized to transport flammable

liquids; this was confirmed by truck tank manufacturing records

(Section 5.4).

Figure 1. Typical vacuum truck used to haul oilfield waste liquids.

1.3.3 BLSR Operating, Ltd.

The BLSR facility is located 5 miles north of Rosharon, Texas, on

FM521. BLSR employed 18 personnel. The facility has been in

operation since the mid 1980s and is currently permitted by RRC6 to

operate five U.S. Environmental Protection Agency (EPA) Class II7
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waste liquid injection wells. It operates on a 24-hour/day, 7-day/

week schedule.

1.4 BS&W Handling

1.4.1 Generation of BS&W

In gas well operation, the wellhead gas stream flows through

separators to remove produced water and liquid hydrocarbons

(condensate):

 The water is stored in an aboveground storage tank.

 The condensate is passed through a heater-treater that breaks

down the hydrocarbon/water emulsion.

Condensate consists primarily of hydrocarbon liquid with trace

amounts of contaminants, including water, paraffin, sand, and other

materials. It is stored in aboveground storage tanks (Figure 2), where

resident time provides further separation of the liquids and remaining

entrained solids. BS&W settles to the bottom of the tank, and the

lower specific gravity condensate floats on top.8

Figure 2. CJ Waller lease water and condensate storage tanks.

8

Specific gravity is the ratio of the density of a liquid compared to water. A lower

specific gravity liquid (<1.0) is lighter than the equivalent volume of water and will

float on top of water.

Condensate consists primarily of

hydrocarbon liquid with trace amounts

of contaminants, including water,

paraffin, sand, and other materials.

BS&W settles to the bottom of the

tank, and the lower specific gravity

condensate floats on top.
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When the BS&W level in the storage tank exceeds a preset value,

usually 8 to 10 inches, the Noble Energy contract gauger9 notifies

the waste hauler to remove it from the tank. The gauger verbally

informs the waste hauler of the specific well site, tank(s), and volume

of waste liquid to be removed. In accordance with DOT requirements, Noble Energy is responsible for identifying both the DOT

hazard class of BS&W and the quantity of liquid to be transported,10

in addition to complying with all other applicable hazardous materials

regulations. The contract gauger may provide this information to the

waste hauler.

The waste hauler supplies the vacuum trucks and drivers to remove

BS&W or other waste liquids from the storage tanks and to transport

the material to approved E&P disposal sites.

1.4.2 Removal and Transport

The contract gauger informs the waste hauler of the quantity of

liquid to be removed, stated in barrels of liquid or in inches of height

in the storage tank.11 The vacuum truck driver is then dispatched to

the well site to remove and transport the waste liquid as follows:

 Identify the correct tank(s) and quantity of liquid to be removed.

 Insert a flexible hose through the top of the tank or connect it

to the storage tank drain manifold (Figure 3), and then connect

the hose to the vacuum truck tank inlet.

 Operate the vacuum pump and the appropriate valves until the

specified quantity of liquid is removed from the storage tank.

 Close the valves, remove the liquid from the hose, and disconnect all hoses from the storage tank and vacuum truck tank.

9

The gauger is a contractor to Noble Energy who is responsible for daily inspection of

well site equipment, minor maintenance, adjustments, transferring fluids between tanks,

and recording water and condensate levels in the storage tanks.

10DOT 49 CFR 173.22.

11The standard 12-foot-diameter storage tank holds 1.67 barrels (70.1 gallons) per inch

of height.

Figure 3. Condensate tank drain

manifold and valves.

Noble Energy is responsible

for identifying both the DOT hazard

class of BS&W and the quantity

of liquid to be transported . . .
18

The objective is to remove only BS&W from the bottom of the

storage tank. It is important that the driver minimize the removal of

condensate because:

 Condensate is an important source of revenue for the producer.

 Condensate is a flammable liquid; mixing it with BS&W may

increase the flashpoint of the mixture to also meet the definition

of a flammable liquid (Section 3.2.3).

All T&L drivers and other waste hauler drivers interviewed by CSB

stated that they were clearly instructed to avoid removal of condensate when removing BS&W from the storage tanks. However, the

ability to avoid condensate removal is dependent on the technique

the driver uses to measure the storage tank contents. Some waste

hauler drivers report that they use a gauge line12 to “color cut”13 the

contents of the storage tank, providing an actual measurement of

BS&W removed. Other drivers use the gauge line only to measure

the total height of condensate plus BS&W in the storage tank before

and after removal of the liquid. Some drivers use the sight gauge

mounted on the truck tank (Figure 4) to estimate the amount of liquid

removed from the storage tank.

The T&L driver prepares a service work order for the liquid transported. It includes the waste hauler’s name, truck ID, driver’s name,

producer’s name and well number, well lease name, truck size, date

and time, description of work, total charges, and estimated quantity

of liquid removed.

Other than information listed on the service work order provided

with invoicing, T&L provides no records to Noble Energy that

accurately document how much BS&W is actually removed from a

tank, nor does the gauger measure or record BS&W height in the

tank. The only record at the well site is through a subsequent tank

level measurement by the gauger or condensate hauler. This can

occur up to 1 day after BS&W is removed. The storage tank might

12Gauge line is a rope or chain weighted on the bottom and indexed in standard length

increments (e.g., by foot). It is lowered into the storage tank to measure the height of

liquid.

13Color cut is a procedure whereby a chemical is applied to the gauge line that changes

color when it comes in contact with water, a significant constituent of BS&W.

Figure 4. Typical vacuum truck tank

sight gauge.

. . . The ability to avoid condensate

removal is dependent on the technique

the driver uses to measure the storage

tank contents.

. . . There is no accurate measurement

of how much condensate is included

in the BS&W loaded into the trucks.
19

continue to receive liquid from the producing well during and after

removal of BS&W. Thus, there is no accurate measurement of how

much condensate is included in the BS&W loaded into the trucks.14

1.5 BS&W Disposal

The BLSR disposal facility contains two waste liquid unloading

stations—the saltwater disposal station and the mud disposal and

washout pad (Figure 5). These stations are used to receive E&P

waste liquids, including saltwater, freshwater, used drilling mud,15

and BS&W.

14Noble Energy contracts with an oil hauler to remove and transport produced

condensate/oil. The oil hauler prepares a “run ticket” or “refusal ticket” depending on

the BS&W level in the bottom of the storage tank. In either case, the ticket accurately

documents the BS&W level and the total liquid volume. However, this information is

not routinely provided to the waste hauler for use when removing BS&W from the

storage tank.

15Drilling mud is a fluid used to lubricate the drill string, line the walls of the well, flush

cuttings to the surface, and create enough weight to prevent blowouts.

Figure 5. BLSR facility layout.

Saltwater disposal 

station 

5,000-bbl 

saltwater storage 

tank 

Office 

N

Recovered condensate 

storage tanks (400 bbl) 

48- x 65-ft covered mud 

disposal/washout pad 

(fire location) 

Waste liquid 

agitator tank 

Oil/water separation 

tank 

Drivers’ shed, 

storage 

Electric 

panel/storage shed 

Mixed water & mud 

holding tanks 
20

1.5.1 Saltwater Disposal Station

The saltwater disposal station is used to unload “clean” salt and fresh

produced water from oil and gas wells. Using a flexible hose connected to the vacuum truck and the truck-mounted vacuum pump,

the driver transfers the truck contents to temporary holding tanks.

Over time, the water, sand, and other solids debris entrained in the

water sink to the bottom of the tank. Highly flammable condensate

and crude oil, which might be present in the produced water, float

on top. BLSR employees transfer this condensate/crude oil to the

recovered condensate storage tanks. The condensate is sold to

refineries; all remaining waste liquid is injected into the disposal wells.

1.5.2 Mud Disposal and Washout Pad

Although BS&W may contain significant amounts of recoverable

condensate/crude oil (Section 3.1.2), it is typically unloaded at the

mud disposal and washout pad. BLSR designed and built the mud

disposal and washout pad for unloading high-viscosity drilling mud

and other waste liquids heavily contaminated with sand and other

materials, and for rinsing out empty vacuum truck tanks with highpressure freshwater.

There are no provisions for recovering condensate/crude oil from the

waste liquid that is unloaded onto the pad. It is injected into the

disposal wells, as discussed below.

The 48- by 65-foot mud disposal pad is equipped with specialized

pumps and other equipment capable of handling highly viscous and

erosive waste liquids, including drilling mud, and paraffin and scale

removed from pipelines. After the vacuum trucks are positioned on

the pad, BLSR employees open the tank drain valves. Waste liquid

splashes onto the large truck bumper (Figure 1) and then onto the

pad. If the liquid does not adequately drain from the truck tank, the

driver operates the truck-mounted vacuum pump. BLSR employees

use high-pressure water hoses to dilute the high-viscosity materials,

The BLSR disposal facility contains

two waste liquid unloading stations—

the saltwater disposal station and the

mud disposal and washout pad.

There are no provisions for recovering

condensate/crude oil from the waste

liquid that is unloaded onto the [mud

disposal and washout] pad.
21

wash out the tanks, and wash the mud and other debris on the

concrete pad to the sump area.

Two hydraulically operated lift pumps (Figure 6) transfer the waste

liquids through polyvinyl chloride (PVC) pipes to an open-top waste

liquid agitator tank located 40 feet west of the pad, or to the mixed

water and mud holding tanks located about 70 feet south of the pad

(Figure 5). Flexible hoses connect each pump to the PVC transfer

pipes. Additionally, the pump discharge can be connected to a PVC

header on the inside west wall of the pad to recirculate the liquid

and further dilute the mud. Significant volumes of waste liquid,

including potentially flammable BS&W, typically accumulate when

offloading onto the concrete pad; the sump pumps have a lower

flow capacity than multiple draining vacuum truck tanks.

The mud disposal and washout pad has a 3-degree slope, to a

maximum depth of approximately 20 inches (Figure 7). A 12- by 12-

inch wooden beam running the length of the pad, approximately 13

Figure 6. Pad area hydraulic sump pumps and wooden stop beam.

Significant volumes of waste liquid,

including potentially flammable

BS&W, typically accumulate when

offloading onto the concrete pad . . .
22

feet from the back wall, protects the sump pumps by preventing

trucks from backing too far onto the pad.

A corrugated roof canopy, approximately 17 feet high, covers the

pad. Corrugated panels are also used along the north side of the pad

to block the cold winter winds. High-pressure water hoses were

suspended from the canopy for use in washing the truck tanks and in

diluting high-viscosity mud both in the truck tank and on the pad

area.

A 220-volt electrical service feed and circuit breaker box are attached

to the southwest canopy support. Fluorescent lights attached to the

canopy ceiling were used for nighttime operations. Droplights were

suspended from the canopy. A large radial fan attached to the

canopy was used as needed to vent noxious vapors during washing

operations. With the exception of the droplights, none of the

electrical conduits, fixtures, or boxes were certified for use in a

flammable environment.

“No smoking” signs were posted around the pit area on the canopy

support legs and on the nearby drivers’ shed wall. An eyewash and

chemical shower station is located 8 feet from the southeast corner of

the pad.

With the exception of the droplights,

none of the electrical conduits,

fixtures, or boxes were certified for

use in a flammable environment.
23

1.5.3 Other Facility Equipment

The BLSR facility included five water storage tanks and three storage

tanks for recovered condensate, which was periodically sold to oil

refiners. Injection well equipment included both electric motor

pumps and gas/diesel pumps for use during power outages.

The main office was located at the southwest corner of the facility,

about 100 yards from the pad area (Figure 5). A small office/storeroom—referred to as the drivers’ shed—was located 8 feet south of

the pad. It was used by the truck drivers to prepare the BLSR

delivery slips and wait for their trucks to be drained or cleaned by

BLSR employees. The facility had a few additional utility sheds,

including the electric circuit breaker storage shed located 8 feet west

of the pad.

Figure 7. Layout of mud disposal and washout pad,

with T&L vacuum trucks positioned as on January 13, 2003.

Fatality Injured worker 
24

1.5.4 Operating Procedures

and Worker Training

BLSR management had no written procedures for truck unloading,

operation of systems, or emergency response. Employees learned

their tasks exclusively through on-the-job training by BLSR management and experienced workers. Limited, general workplace hazard

training was provided to some employees (using Spanish and English

videotapes provided by the Texas Workers’ Compensation Insurance

Fund). With the exception of a summary of potential flammability

hazards associated with waste liquids delivered to the facility, the

employees received no other training on chemical hazards, nor were

they provided with material safety data sheets (MSDS).

In terms of which unloading station to use, the only guidance provided by BLSR to the truck drivers was that “clean saltwater” was to

be unloaded at the saltwater disposal station, and “dirty” water was

to be unloaded at the mud disposal and washout pad. Drivers were

also aware that drilling mud or other high-viscosity waste liquids

could be unloaded only at the mud disposal and washout pad.

Attempting to unload such material at the saltwater disposal station

could plug the piping and possibly damage the well injection pumps.

BLSR provided only verbal instructions to explain which piping and

valves were to be used at the saltwater disposal station.

In practice, BLSR relied on the truck drivers to decide which of the

two unloading systems to use. Because all waste liquids—including

clean saltwater and BS&W—could be easily and quickly unloaded at

the mud disposal and washout pad rather than at the saltwater

disposal station, drivers typically chose the former unless there was a

backlog of trucks waiting to be unloaded. To avoid having to go to

both areas, drivers also routinely used the mud disposal and washout

pad to unload clean saltwater if the truck tank also required rinsing.

BLSR management had no written

procedures for truck unloading,

operation of systems, or emergency

response.

In practice, BLSR relied on the truck

drivers to decide which of the two

unloading systems to use.
25

2.1 The Incident

At approximately 4:00 pm on January 13, 2003, the drivers of

T&L trucks #1004 and #1003 collected BS&W from the CJ

Waller and Roberts lease site condensate storage tanks, respectively.

Both drivers relied only on the vacuum truck sight gauge to determine

the volume of liquid removed from the storage tanks.

Oil hauler refusal tickets from the CJ Waller lease site recorded the

BS&W level as 13 inches and 15 inches in two tanks—46 barrels

total. The T&L driver reported 50 barrels of liquid removed from

the tanks on the service work order. The records for the truck

dispatched to the Roberts lease were destroyed in the fire.

The trucks arrived at BLSR within a few minutes of each other.

Each driver backed onto the mud disposal and washout pad to

unload BS&W and have the truck tanks rinsed out. The trucks were

approximately 16 feet apart and equally distant from each side of the

pad (Figure 7). Based on the service work order recovered from the

drivers’ shed and the vehicle license plate, the truck parked on the

north side was #1004; the truck parked on the south side was

#1003.

BLSR employees were in the process of diluting drilling mud that

had accumulated from earlier deliveries by adding clean water and

recirculating the liquid through the hydraulic pump and back into

the pad area. Flexible hoses connected the pump to the PVC

header mounted on the wall and from the header back onto the

pad. Winds were from the west, at less than 5 miles per hour; the

temperature was about 50oF.

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. Two BLSR employees

opened the valves to drain the truck tanks. One BLSR employee

climbed onto the truck parked on the north side of the pad and

began to remove the manway cover bolts in preparation for the

washout (Figure 8).

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. A BLSR employee standing near the

electric shed northwest of the canopy ran to the drivers’ shed.

2.0 Description of Incident

Figure 8. North side truck manway bolts

partially removed.

BLSR employees were in the process

of diluting drilling mud that

had accumulated from earlier

deliveries by adding clean water and

recirculating the liquid through

the hydraulic pump . . .

. . . 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.
26

BLSR employees and the driver of the north truck reported that they

heard loud backfiring. The two drivers and a BLSR employee exited

the shed and ran toward the trucks. The second (south) truck

engine began the same violent racing. The BLSR employee proceeded to the area between the trucks, and each driver approached

his respective side door.

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

two trucks were completely engulfed by fire, as was the west end of

the pit containing the liquid that had drained from the trucks.

2.2 Emergency

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 Angleton VFD and Brazoria

County Sheriff’s Department were also dispatched. 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.

Two BLSR employees caught in the deflagration were fatally burned.

The two T&L drivers were severely burned and life-flighted to

Herman Hospital; one succumbed to his injuries 46 days after the

incident. 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.

Response

Two BLSR employees caught in the

deflagration were fatally burned.

The two T&L drivers were severely

burned . . . one succumbed to his

injuries 46 days after the incident.
27

2.3 Property Damage

The fire totally destroyed the two T&L trucks. Although none of the

emergency responders opened the hood on the north truck during

firefighting operations, debris from the hood was found in front of

the truck, indicating that it was forced completely open by the

deflagration pressure wave. The tank vent and drain valve packing

and seals on both trucks were destroyed, as indicated by lack of

resistance when moving the valve actuator handle.

The weight of the valve handle and internal components caused

each of the drain valves to return to the closed position during the

fire (Figure 9). However, even in the closed position, the firedamaged valves allowed liquid to drain from the tanks. The sight

glass was burned away, and the tanks were empty. All vacuum hoses

were destroyed; only the coiled metal wire and connector fittings

remained. 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.

Figure 9. Truck tank drain valves

in closed position.
28

The canopy above the unloading pad sustained major heat damage

(Figure 10). The electrical service line attached to the southwest

canopy support column was severed, and all ceiling-mounted lighting

and the vent fan were destroyed. The emergency eyewash station

and shower next to the drivers’ shed, the equipment switch panel on

the northwest corner wall adjacent to the concrete pad, and equipment in the electrical shed sustained significant radiant heat damage.

Fire and smoke damaged the storage room attached to the drivers’

shed.

The fire department directed that the accumulated water and other

liquid in the sump area be removed. A waste hauler transferred the

liquid to two vacuum trucks and disposed of it at another licensed

saltwater disposal well facility. Emergency responders completed

their work at 10:00 pm.16 There was no environmental damage.

16Brazoria County Sheriff Incident Report #03010143, January 22, 2003.

Figure 10. Mud disposal and washout pad, showing burned trucks and damaged canopy.
29

3.1 Hazard Recognition

Waste liquids generated at E&P sites include saltwater and

freshwater, drilling mud, and BS&W—all of which can

contain some flammable hydrocarbon liquids. The actual flammability hazard is dependent on the source of the liquid, ambient temperature, mixing during transfer to the vacuum truck, and other process

variables.

Through interviews, CSB determined that many personnel in the

E&P industry recognize the potential flammability hazard17 associated

with BS&W and other waste liquids, and implement safe work

practices when handling and transporting these hazardous materials.

However, more than two-thirds of those interviewed stated that they

believe all BS&W possesses a negligible flammability hazard.

It is the responsibility of the offeror/shipper18 to properly classify and

describe materials (49 CFR 172, 173). However, CSB was unable

to find any documents to support an analysis to determine the hazard

class of the material being offered for transport by Noble Energy

(e.g., MSDSs) or any other generator of the material. Haulers who

are not notified by the shipper, or do not otherwise recognize the

specific flammability hazard of BS&W, may fail to take the necessary

precautions to prevent the occurrence of a hazardous materials

incident. Furthermore, disposal facility personnel who incorrectly

assume that BS&W is either nonflammable or presents a very low

flammability hazard take few or no precautions to control flammable

vapor generation and ignition sources.

The following Noble Energy, T&L, and BLSR management system

failures contributed to this incident:

 Failure to recognize the potential flammability of BS&W, as

defined by OSHA and DOT (Table 1), and to properly classify

the material.

 Failure to implement work practices at the well site and at the

waste disposal facility to minimize the release of flammable

vapor from BS&W and to safely handle releases.

3.0 Incident Analysis

17This recognition refers to an awareness that BS&W might ignite and burn. It does not imply

knowledge of OSHA or DOT definitions of flammable liquids.

18The term “shipper” is the same as the term “offeror” used in the transportation industry.

Waste liquids generated at E&P sites

include saltwater and

freshwater, drilling mud, and

BS&W—all of which can contain

some flammable hydrocarbon liquids.

. . . More than two-thirds of those

interviewed stated that they believe all

BS&W possesses a negligible

flammability hazard.
30

 Failure to recognize potential ignition sources when handling

BS&W.

 Failure to adequately train employees:

 On techniques to minimize the potential hazards of flammable liquids.

 On response to a system malfunction or site emergency.

 On general awareness of and familiarization with hazardous

materials.19

 On specific job functions.20

1949 CFR 172.704(a)(1). Each hazmat employee shall be provided general awareness training designed to provide familiarity with the requirements of this subchapter,

and to enable the employee to recognize and identify hazardous materials consistent

with the hazard communication standards of this subchapter.

2049 CFR 172.704(a)(2)(i). Each hazmat employee shall be provided functionspecific training concerning requirements of this subchapter, or exemptions issued

under Subchapter B of this chapter, which are specifically applicable to the functions

the employee performs.

(a) OSHA 1A Flammable Liquid: Flashpoint below 73oF and boiling

point below 100oF.

OSHA 1B Flammable Liquid: Flashpoint below 73oF and boiling

point above 100oF.

OSHA IC Flammable Liquid: Flashpoint above 73oF and below

100oF.

DOT 3 Flammable Liquid: Flashpoint below 141oF.

Flashpoint (oF) Flammable Liquid

-100 Phillips Petroleum sweet condensate

-50 Unleaded gasoline

-40 Amerada Hess sweet condensate

30 CSB BS&W samples, CJ Waller and

Roberts leases

45 Toluene

100 Diesel fuel

Table 1

Flammable Liquid Flashpoints (a)
31

3.1.1 Flammability Hazard

of Production Liquids

Producers and haulers clearly recognize that producing well products—both oil and condensate—are flammable liquids. These liquid

products are handled and transported according to Federal and state

regulations. However, CSB found that the majority of those questioned during the investigation do not believe that BS&W exhibits a

flammability hazard, even though it can originate from highly flammable condensate (Section 3.1.2).

OSHA does not require specific labeling of containers holding

hazardous chemicals (e.g., flammable liquids) if the employer has an

alternative method of communicating the hazard information. CSB

observed that the labeling on well site storage tanks containing

flammable liquids may not meet the OSHA standard. The tank ID

number stenciled on the front of the storage tank may not be sufficient to adequately communicate the hazard to employees or contractors.

Of eight well sites visited after the incident, only three had labels

identifying that the tank contained a flammable liquid. The other five

sites had no markings on any of the storage tanks to communicate the

hazardous material contents (Figure 11).21 The only warning signs

at these facilities consisted of “no smoking” signs attached to either

the property fence or to the fence surrounding the storage tanks

and associated equipment.

CSB concluded that labeling the storage tanks with the appropriate

flammability hazard identification would not change the opinion of

those in the industry who maintain that BS&W is not flammable—

nor would labeling, by itself, have prevented the January 13

incident. However, labeling is likely to improve worker awareness

and help ensure that less experienced individuals can distinguish tanks

containing flammable condensate from tanks containing water.

21Following the January 13, 2003, incident at BLSR, Noble Energy attached labels to

product and waste storage tanks at the CJ Waller and Roberts well sites, identifying

the contents as DOT Class 3 flammable liquids. However, the product and waste

storage tanks at three other Noble Energy well sites did not have any hazard class

labeling on February 11, 29 days after the incident.

Figure 11. Unlabeled flammable

condensate storage tanks,

CJ Waller lease.

Producers and haulers clearly

recognize that producing well

products—both oil and condensate—

are flammable liquids.

. . . The majority of those questioned

during the investigation do not believe

that BS&W exhibits a flammability

hazard, even though it can originate

from highly flammable condensate.
32

BLSR management reports that drivers have actually delivered

condensate to the disposal facility when they thought they had

collected water or BS&W from a well site storage tank; they had

inadvertently removed saleable product liquid by drawing from the

wrong tank. Proper storage tank labeling might help prevent future

occurrences of this dangerous and wasteful practice.

CSB observed that the condensate storage tanks at two gas pipeline

metering stations in the area, owned by a gas transmission pipeline

company, were labeled with the National Fire Protection Association

(NFPA) hazard diamond displaying a flammability rating of 4 (very

volatile flammable liquid; Figure 12).

Figure 12. Condensate storage tank located at gas regulator station.
33

22 API gravity is a term used by the petroleum industry to express the relative quality, or

heating value, of petroleum liquids. A high API gravity (low specific gravity) indicates a

lighter crude with better heating value than a crude with low API gravity (high specific

gravity).

23 Flashpoint is defined as the minimum temperature at which a liquid releases sufficient

vapor to form an ignitable mixture with air near the surface.

24The gauger measured 18 inches of water in the condensate tank. The water was

deliberately put in the tank to add sufficient weight to prevent overturning by high storm

winds.

3.1.2 Flammability Hazard

of Waste Liquids

Because BS&W and other waste liquids have a lower API gravity22

(higher specific gravity) than condensate and oil, they gradually settle

to the bottom of the storage tank. The measured flashpoint23 of

BS&W is dependent on the amount of volatile hydrocarbons contained in the mixture.

A higher temperature of the tank contents promotes separation of the

hydrocarbons from BS&W. With the passage of time, more volatile

hydrocarbons migrate up into the condensate, reducing the flammability of BS&W. However, there are no data to suggest a minimum

residence time to separate sufficient volatile hydrocarbons from

BS&W such that the flashpoint is increased above the hazardous

flammable liquid threshold.

Production records for the CJ Waller and Roberts leases indicate that

each well, in 48 to 72 hours, produces enough liquid to fill one 400-

barrel tank. At this rate, it may be necessary to remove BS&W from

the tank two to three times a week to maintain a satisfactory gas

generation rate for the well. Establishing a minimum hold time to

ensure that BS&W is no longer considered a flammable liquid before

removal from the tank may not be a practical solution to reducing the

hazard.

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. (For comparison, the

flashpoint of condensate is about –36oF, and the flashpoint of gasoline is about –45oF.) Only one of the storage tank BS&W samples

had a flashpoint above 141oF.24 A tank bottom “thief” (Figure 13)

was used to ensure that only BS&W was withdrawn from the tanks. Figure 13. Gauge hatch and tank

“thief” showing 13 inches of BS&W

below condensate.

The measured flashpoint of BS&W

is dependent on the amount of

volatile hydrocarbons contained

in the mixture.
34

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. 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. Appendix A summarizes the test

results. For comparison, Table 1 (shown on page 30) lists flashpoint

values of selected flammable liquids.

As discussed earlier in Section 3.0, the E&P industry generally recognizes the significant flammability hazard of condensate liquids, but

may not recognize the potential flammability hazard of BS&W and

other waste liquids. CSB determined that some BS&W—like condensate—may produce sufficient flammable vapors to pose an

ignition hazard. Inadequate recognition of potential flammability

hazards results in inadequate hazard identification, inadequate hazard

communication, and failure to safely handle and transport these

materials.

3.2 Safe Handling

Gas production well operations generate saleable condensate and

liquid waste. The condensate is collected at production gas well sites

and sold to refineries for use as feedstock. Because the flashpoint of

condensate is significantly below 141oF, it is a DOT Class 3 flammable liquid25 requiring special handling and transportation (Section

5.4). It may also be classified as an OSHA Class IB flammable liquid

requiring specific equipment design to minimize the facility fire hazard

(Section 5.3). E&P industry personnel, including haulers and disposal operators, understand the flammability hazard of condensate

and handle it accordingly. The flammability characteristics of condensate are similar to gasoline.

25 49 CFR 173.120.

of BS&W

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.

CSB determined that some BS&W—

like condensate—may produce

sufficient flammable vapors to pose

an ignition hazard.

Because the flashpoint of condensate

is significantly below 141oF, it is a

DOT Class 3 flammable liquid . . .

It may also be classified as an OSHA

Class IB flammable liquid . . .
35

As discussed in Section 2.0, CSB determined that a flammable vapor

cloud was ignited. There are two scenarios for the source of the

flammable vapor—waste liquid offloaded in the disposal pad earlier

in the day, or waste liquid delivered by one or both of the T&L

vacuum trucks. Each scenario is discussed below.

3.2.1 Waste Liquid Deliveries

Prior to Incident

CSB interviewed BLSR personnel who were working on the day of

the incident. As summarized in Table 2, work ticket records identified

25 trucks (owned by 11 permitted waste liquid haulers) that used the

BLSR facility between 12:00 am and 3:00 pm on January 13, before

arrival of the T&L trucks involved in the incident.

The last truck, containing oil-based drilling mud,26 was emptied on

the pad and washed out approximately 2 hours before the T&L

trucks arrived. BLSR employees reported that they had not completed diluting and washing the drilling mud into the sump pump

26Oil-based drilling mud is a specialized well drilling fluid containing mineral oil; it has a

flashpoint in excess of 350°F and is not a flammable liquid.

There are two scenarios for the

source of the flammable vapor—

waste liquid offloaded in the disposal

pad earlier in the day, or waste liquid

delivered by one or both of

the T&L vacuum trucks.

Work Description Total Trucks

Empty tank washout 10

Deliver oil-based drilling mud

and tank washout 2

Deliver dirty water 6

Deliver clean water 3

Deliver well fracturing waste liquid 1

Deliver well plugging returns 1

Deliver BS&W and tank washout 2

Table 2

BLSR Delivery Summary for January 13, 2003
36

intakes; a significant amount of mud remained on the concrete pad

behind the wooden stop beam.

CSB determined from interviews that there was negligible drilling

mud or other waste liquid above the stop beam prior to arrival of the

T&L trucks. The concrete pad surface down to the stop beam had

been thoroughly washed. Mud and other materials drained from the

previous truck deliveries that day had accumulated behind the beam.

Furthermore, waste haulers familiar with BLSR operations confirmed

that BLSR kept the concrete pad reasonably clean to preclude

creating a slipping hazard for workers and truck drivers. The drilling

mud and debris observed above the wooden stop beam after the

incident were most likely forced past the beam by high-pressure

water spray during firefighting.

There were two earlier BS&W deliveries on January 13 and two

deliveries of drilling mud (which can contain trace amounts of

hydrocarbons). However, area cleaning activities and the 2 hours

between the previous truck delivery and the T&L vacuum truck

arrivals would most likely have allowed any flammable vapor to

dissipate. It is unlikely that the flammable vapor that ignited originated

from the waste liquid remaining in the pad from the earlier deliveries.

3.2.2 Waste Liquid Delivered

by T&L Trucks

CSB was unable to collect any sample of the liquid that was delivered

to the BLSR facility in the T&L vacuum trucks on January 13. It was

either consumed in the fire; or diluted with firewater, fire debris, and

waste liquid from the mixed water and mud holding tank,27 and

removed from the scene during cleanup. Internal visual examination

of the vacuum truck tanks 2 days after the incident showed both to

be dry, with a negligible amount of residue. Either all of the liquid

tank contents drained out before or during the fire, or the heat boiled

any remaining liquid out of the tanks.

27The fire destroyed a PVC valve on the pipe connecting the mud disposal and washout

pad to the mixed water and mud holding tank. The tank contents drained back into the

pad area until a valve at the base of the tank was closed sometime during the firefighting

activities.

. . . Area cleaning activities and the

2 hours between the previous truck

delivery and the T&L vacuum truck

arrivals would most likely have

allowed any flammable vapor

to dissipate.
37

One T&L shipping paper (service work order #105754) was

recovered in the drivers’ shed. It reported that T&L vacuum truck

#1004 delivered 50 barrels of BS&W28 from the CJ Waller lease.

The remains of the truck on the north side of the pad were identified

as truck #1004. Eyewitnesses at the CJ Waller lease confirmed that

this truck picked up BS&W from the condensate tanks around the

same time recorded on the work order.

The shipping paper for the second T&L truck, #1003, was not

recovered. From interviews with Noble Energy well operations

personnel, other T&L employees, and the Noble Energy gauger—

and written records of condensate tank daily measurements—CSB

determined that truck #1003 picked up BS&W from condensate

tanks at the Roberts lease prior to arriving at BLSR.

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.

3.2.3 Storage Tank Draining Procedures

The flammability of liquid in the waste hauler’s vacuum truck tank is

highly dependent on the procedure used to remove BS&W from the

condensate storage tank and the physical characteristics of the tank

contents. Figure 14 shows the position of the 4-inch-diameter

condensate withdrawal nozzle and the 3-inch-diameter tank drain

nozzle in relation to the bottom of a typical condensate tank. The

flat-bottom, 12-foot-diameter tank has no internal piping.

If the total depth of BS&W drops below approximately 4 inches,

condensate begins to flow out of the drain nozzle. If condensate is

removed with BS&W, the hydrocarbon content of liquid in the

vacuum truck tank is generally higher than the hydrocarbon content

of BS&W. For example, if the BS&W depth starts at 10 inches (700

gallons, or 16.7 barrels) and the driver withdraws 8 inches of liquid

28Oil hauler refusal tickets recorded only about 20 barrels of BS&W in each of the two CJ

Waller lease storage tanks (40 barrels total) 8 hours prior to the incident.

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.

If condensate is removed with BS&W,

the hydrocarbon content of liquid

in the vacuum truck tank is

generally higher than the

hydrocarbon content of BS&W.
38

(presumably BS&W) through the drain nozzle, as much as 2 inches

of condensate (140 gallons) is mixed with BS&W. The liquid

“waste” in the truck tank is actually 25 percent highly flammable

condensate.

Some well operators require that vacuum truck drivers insert a hose

through the gauge hatch on top of the tank to pull out BS&W rather

than use the bottom drain, in the belief that this technique removes

less condensate. However, pulling BS&W from the top draws

condensate into the vacuum tank at least equal to the amount of

condensate that fills the hose when it is inserted down to the bottom

of the tank. Furthermore, this procedure requires close monitoring of

the end of the hose to preclude it from moving up into the condensate during unloading. It also exposes the driver to additional work

hazards, as noted below:

 Work must be performed on a platform at least 15 feet above

the ground (Figures 2 and 11).

 Heavy hoses must be carried up the access stair, inserted into

the storage tank, and tied to the catwalk railing.

 A hose leak could siphon flammable liquid out of the tank onto

the ground.

Figure 14. Vertical spacing of storage tank nozzles

(180o apart around circumference of tank).

condensate

b s & w

4" draw line

3" drain line

4"

12"

20'

12' dia.

b s & w

condensate
39

2949 CFR 173.120.

Even if the “pure” BS&W in the bottom of the storage tank has a

flashpoint above 141°F (a nonflammable liquid as defined by

DOT29 ), the very narrow tolerance range involved with removal of

BS&W increases the likelihood that the contents of the vacuum truck

tank will have enough hydrocarbon liquid mixed in to lower the

flashpoint below 141°F. The resulting mixture would then be

classified as a DOT Class 3 flammable liquid, requiring special

handling.

The viscosity of BS&W and the flow rate through the drain or

suction hose also influence the amount of condensate that might be

removed. BS&W with higher viscosity than the condensate or with

a high flow rate causes a vortex effect (i.e., funneling) around the

storage tank drain outlet or suction hose end. The liquid is drawn

down much faster in the area near the removal point because there

is insufficient time for horizontal flow to maintain the BS&W–

condensate interface level across the entire tank diameter. This effect

is further amplified because the drain and gauge hatch are located

on, or very close to, the side of the tank—resulting in a much longer

horizontal distance, typically up to 12 feet, for BS&W to flow to the

removal port. Condensate is thus drawn into the removal port more

quickly than when the flow rate is slow enough to maintain the

interface level across the tank.

CSB determined that some waste haulers do not recognize the

potential for removing significant quantities of flammable condensate

along with BS&W. Control of this process is dependent on the

measurement technique used by the driver, and the attentiveness of

the driver in detecting condensate in the drain piping or vacuum

truck tank, or in recognizing changes to the vacuum pump sound as

condensate is drawn into the tank. However, even the best control

procedure will not prevent condensate removal when BS&W drops

below the top of the discharge port.

. . . The very narrow tolerance range

involved with removal of BS&W

increases the likelihood that

the contents of the vacuum truck tank

will have enough hydrocarbon liquid

mixed in to lower the flashpoint

below 141°F.

The viscosity of BS&W and the flow

rate through the drain or suction hose

also influence the amount of

condensate that might be removed.

. . . Even the best control procedure

will not prevent condensate removal

when BS&W drops below the top

of the discharge port.
40

3.3 Ignition Sources

As discussed below, there were five possible vapor cloud ignition

sources—the vacuum truck diesel engine, vacuum truck electrical

system, static electricity discharge from the offloading liquid, personnel smoking, and facility electrical wiring. CSB identified the diesel

engine as the most likely ignition source, though high-temperature

engine components and static electricity discharge cannot be ruled

out. The other two possibilities were determined to be unlikely.

3.3.1 Vacuum Truck Diesel Engine

The vapor cloud could have been ignited by open flame or spark, or

by a high-temperature surface. Each vacuum truck engine provided

two possible ignition sources, as discussed in Sections 3.3.1.1 and

3.3.1.2.

3.3.1.1 Engine Malfunction Caused

by Flammable Vapor

A possible source of ignition from the engine is a backfire through the

intake or exhaust. Under normal operating conditions on a fuelinjected engine, there is no flammable vapor in the intake and exhaust systems. However, if the intake draws a flammable vapor, the

engine is likely to backfire through the intake system.

A diesel engine relies on compression to ignite the air/fuel mixture.

Backfire can occur if the addition of a flammable vapor sufficiently

lowers the autoignition temperature (AIT)30 of the mixture in the

combustion chamber to cause it to ignite at a lower pressure (i.e.,

earlier in the compression stroke of the piston). Because the intake

valve has not completely closed before ignition, the flame can travel

back through the open valve and ignite the flammable vapor.

30AIT is the temperature at which a flammable vapor will ignite without an external

source of ignition. AIT decreases with increasing pressure and increasing gas volume.

The vapor cloud could have been

ignited by open flame or spark, or by

a high-temperature surface. Each

vacuum truck engine provided two

possible ignition sources . . .

. . . If the intake draws a flammable

vapor, the engine is likely to backfire

through the intake system . . . Because

the intake valve has not completely

closed before ignition, the flame can

travel back through the open valve

and ignite the flammable vapor.
41

A second mechanism for diesel engine backfire is high engine speed

such that the intake or exhaust valves cannot completely close before

the air/fuel mixture ignites in the compression stroke. The valve

spring rate determines the time required for the valves to close. If the

piston speed (i.e., engine rpm) exceeds the limits of the valve closing

time (a condition known as “valve float”), the air/fuel ignites before

the valves return to the seated position. The flame propagates out of

the combustion cylinder into the flammable vapor-rich intake or

exhaust systems, the components of which can easily be blown apart.

These systems are not designed for the positive pressures generated

by flame ignition.

Blocking the flow of fuel to the combustion chamber by interrupting

power to the fuel pump and injection system stops a typical diesel

engine, like the ones in the T&L trucks. However, if a flammable

vapor continues to be available through the air intake system, the

engine will continue to run even when the fuel system is shut off.

It is then necessary to block the intake or the exhaust gas flow to stop

the engine.31

Some vehicle manufacturers include an emergency shutoff valve as

standard equipment or an option. NFPA (1999) permits installation

of a manual emergency shutdown device on the intake or exhaust

systems to prevent engine overspeed. The U.S. Department of

Labor, Mine Safety and Health Administration, and the U.S. Coast

Guard require air intake shutoff devices in certain applications.

Various Canadian provinces require diesel engine air intake shutoff

devices on well drilling apparatus. However, preventing engine

overspeed eliminates only one of the diesel engine ignition sources.

High-temperature exhaust components may still ignite the flammable

vapor, as discussed in Section 3.3.1.2.

31Manual and automatic intake air shutoff devices are available to accomplish this

function. However, these devices are intended only to prevent physical damage to the

engine, not to prevent a backfire; they may increase the possibility of an accident if they

inadvertently activate while the vehicle is moving.

A second mechanism for diesel engine

backfire is high engine speed

such that the intake or exhaust valves

cannot completely close before

the air/fuel mixture ignites in

the compression stroke.

. . . If a flammable vapor continues to

be available through the air intake

system, the engine will continue to run

even when the fuel system is shut off.
42

The T&L truck engines were not equipped with overspeed protection devices in the intake or exhaust systems. Eyewitness accounts of

the over-revving are clear evidence that the air intake system was

drawing in flammable vapor prior to the deflagration. Eyewitnesses

reported hearing loud backfiring from one of the engines. Examination of the truck engines and debris confirmed that the metal elbow

on the south truck engine (Figure 15) separated from the turbocharger housing—which is a positive indication that the engine

backfired through the intake system, potentially igniting flammable

vapor.

One witness also reported that the hood on the south truck lurched

up just before the vapor ignited, suggesting a high-pressure impulse

around the engine. The elbow and attached short piece of flexible

hose (dark arrow in Figure 16) were recovered and showed no fire

damage, providing further evidence that the fitting had come off and

fallen to the ground before the fire ignited and destroyed the engine.32

32For comparison, evidence suggests that either the north truck engine did not backfire,

or the pressure wave from a backfire was not sufficient to blow the fitting off the

turbocharger. A portion of the elbow was still attached to the turbocharger housing, and

the remainder of the elbow and flexible hose was destroyed.

Figure 15. South truck diesel engine

turbocharger discharge elbow.

Figure 16. Diesel engine exhaust and intake system.

The T&L truck engines were not

equipped with overspeed

protection devices in the intake or

exhaust systems.

Examination of the truck engines and

debris confirmed that the metal elbow

on the south truck engine separated

from the turbocharger housing—

which is a positive indication that

the engine backfired through

the intake system, potentially

igniting flammable vapor.
43

Figure 17. Bent exhaust valve pushtube, south truck

diesel engine combustion chamber #2.

In April 2003, a diesel engine maintenance shop disassembled the

two truck engines to determine if either had incurred internal damage

caused by over-revving, which would support the backfire scenario.

The north truck engine sustained no damage indicative of overspeed.

However, the south truck engine clearly showed evidence of overspeed damage, including a severely bent exhaust valve pushtube

(Figure 17) and bent exhaust valve. CSB determined that backfiring

from the south engine is the most likely source of ignition of the

flammable vapor cloud.

33LFL and UFL are the percent concentrations of a flammable vapor in air that will

support combustion. Concentrations below the lower limit or above the upper limit will

not ignite.

34Amerada Hess Corporation, Material Safety Data Sheet #15017, August 1998.

3.3.1.2 Surface Temperature

If a flammable vapor is within the lower (LFL) and upper flammability

limits (UFL),33 it most likely will ignite if it comes in contact with a hot

surface at a temperature above the vapor AIT. Tests performed on

BS&W samples removed from the CJ Waller lease and transported

in one of the T&L trucks resulted in an AIT of about 560°F. For

comparison, a condensate MSDS34 identifies the AIT as 480°F.

A typical industrial diesel truck engine has many possible heat sources,

including engine block and heads, and exhaust manifold and turbine

housing (Figure 16). The engine block and heads are expected to

. . . The south truck engine clearly

showed evidence of overspeed

damage, including a severely bent

exhaust valve pushtube and

bent exhaust valve.
44

operate at about 200°F, near the boiling temperature of water. The

exhaust manifold temperature is dependent on the engine load and

cooling air provided by the radiator fan and truck speed. Thermal

profile data provided by Cummins Engine show contact temperatures

on the turbocharger mounting flange ranging from 270°F at idle to

more than 1,000°F at full load.

The T&L trucks had been driven at highway speeds from the well

sites to BLSR, a distance of about 10 miles. When they arrived at the

mud disposal and washout pad, they were directed into position and

the unloading process began with minimal delay. CSB determined

that the turbocharger flange surface temperature may have been hot

enough to ignite the flammable vapor. Furthermore, vapor could

have migrated to the turbocharger housing due to airflow from the

engine radiator cooling fan. High temperatures on these engine

exhaust components could have provided an ignition source for the

flammable hydrocarbon vapor.

3.3.2 Vacuum Truck Electrical System

Sparks from the truck electrical system could ignite a flammable vapor

if it is within the LFL–UFL range. Possible sources of electric sparks

on the T&L trucks include damaged wiring, or electrical devices

inside the truck cab or anywhere on the chassis. However, because

of the total destruction of the trucks, it was not possible to identify

any vehicle-mounted electrical circuits as a possible ignition source.

3.3.3 Static Electricity From

Offloading Liquid

Hydrocarbon-based liquids are capable of accumulating a static

charge as they flow through piping systems and hoses, or mix and

slosh during transit. Water mixed in the liquid can exacerbate the

static hazard. Only 0.2 to 0.3 milliJoule (mJ) of spark energy is

needed to ignite vapor from hydrocarbon liquids; for comparison,

static discharge from a human body to another object can exceed

0.4 mJ.

CSB determined that the turbocharger

flange surface temperature may have

been hot enough to ignite the

flammable vapor.

Possible sources of electric sparks on

the T&L trucks include damaged

wiring, or electrical devices inside the

truck cab or anywhere on the chassis.
45

Proper grounding of equipment is critical to dissipating the static

charge buildup to preclude a spark release. API recommends that

trucks always be grounded when loading and unloading liquid, and

also that conducting hoses be used to connect the truck to the

equipment (API, 1999).

A retractable grounding cable was mounted on the rear bumper of

the T&L vacuum trucks (Figure 18). However, there were no

provisions at BLSR for attaching the truck cable to a suitable ground

device. Hoses were not used during the offloading procedure.

Because the trucks were not grounded, unloading of the tank contents may have generated a static electric spark, which could have

ignited the flammable vapor. Although this cannot be ruled out, the

preponderance of evidence, as discussed in Section 3.3.1, suggests

that backfiring caused by engine overspeed is the more likely source

of ignition.

3.3.4 Personnel Smoking

“No smoking” signs were prominently posted around the mud

disposal and washout pad, and BLSR employees avoided smoking in

the area. Eyewitnesses reported that neither driver was smoking

when they arrived at BLSR or prior to the fire. Furthermore, no

eyewitness accounts supported a scenario whereby smoking caused

the vapor cloud to ignite.

3.3.5 Facility Electrical Wiring

The following circuits were located in and around the mud disposal

and washout pad (Section 1.5.2):

 Numerous 110-volt lighting circuits routed on the canopy and

in the drivers’ shed.

 A 110-volt circuit panel in the storage shed.

Figure 18. Truck-mounted ground cable

recoil device.

. . . There were no provisions at BLSR

for attaching the truck [ground] cable

to a suitable ground device.
46

 Motor control switches on the northwest corner of the canopy

near ground level (Figure 19).

 A telephone in the drivers’ shed, which was used immediately

preceding the vapor cloud ignition.

None of these circuits were designed for operation in a flammable

vapor environment.

The lighting in the canopy was used only at night. Switch positions

found on the circuit breaker panel indicated that the lights were not

on at the time of the incident, as supported by eyewitness testimony.

Radiant heat caused the majority of damage to the motor control

switch panel, indicating that the vapor ignition did not originate from

that location. Physical evidence and eyewitness testimony led CSB to

conclude that the vapor cloud was not ignited by a facility electrical

circuit.

Figure 19. Remains of motor control

switch panel.

None of these circuits were designed

for operation in a flammable vapor

environment.

Physical evidence and eyewitness

testimony led CSB to conclude that

the vapor cloud was not ignited by

a facility electrical circuit.
47

4.1 American Petroleum

API provides detailed information on the safe operation of

vacuum trucks and waste facilities, as noted below:

 API Order No. G00004, Guidelines for Commercial Exploration and Production Waste Management Facilities (2001),

provides information on management, operations, and risk

reduction at waste disposal facilities.

 API Recommended Practice 2219, Safe Operation of Vacuum

Trucks in Petroleum Service (1999), provides information on

common hazards and safe work practices and precautions for

vacuum truck operations.

Both documents provide detailed guidance on the safe operation of

equipment and facilities; however, neither addresses the increased

hazards associated with unloading flammable liquids onto open areas.

It is a much safer practice to contain flammable liquids in closed

piping systems during transfer.

BLSR and T&L management were apparently not aware of this API

guidance.

4.2 National Tank

NTTC is a trade association of approximately 180 trucking

companies that specialize in the nationwide distribution of bulk

liquids, industrial gases, and dry products in cargo tank motor

vehicles. Its primary mission is to:

 Enhance the safety of the industry by providing relevant and

useful information to carrier management.

 Exchange information with major shipper organizations to

ensure safe, efficient, and cost-effective transportation policies.

NTTC estimates that more than 70 percent of tank trucks carry

DOT-classified hazardous materials, requiring carrier management

and drivers to possess special knowledge and skills, in addition to

understanding and fully implementing all applicable Federal and state

regulations.

T&L was not a member of NTTC.

4.0 Industry Associations

Institute

Truck Carriers, Inc.
48
49

5.1 U.S. Environmental

The Resource Conservation and Recovery Act (RCRA) of

1976 authorized EPA to regulate certain industrial wastes.

RCRA Subtitle C contains the comprehensive regulatory program for

hazardous waste management. In 1980, Congress specifically

exempted from regulation under RCRA Subtitle C “drilling fluids,

produced waters, and other wastes associated with the exploration,

development, or production of crude oil or natural gas.”35

In July 1988, EPA published a regulatory determination to continue

the exemption of these oil and gas wastes.36 It clarified the scope of

the exemption to apply to “those wastes uniquely associated with

primary field operations.” In March 1993, EPA again refined the

definition to address the applicability of the exemption to wastes

generated by crude oil reclaimers and other processors, and storage

and transporter activities.37 It provided that:

 “Change-of-custody” (i.e., sale of goods from shipper to hauler

or others) applies to product only, not to waste.

 Offsite transportation of exempt waste does not negate the

exemption.

 Waste derived from treatment of exempt waste, including

recovery of product, generally remains exempt.

 Vacuum truck rinse liquid is exempt provided that the truck

contains only E&P exempt waste, and the water is not subject

to RCRA Subtitle C.

The Texas RRC is responsible for oilfield waste materials management in Texas under a federally approved program.

5.2 Texas Railroad

The State of Texas has more than 6,000 oilfield operators and

350,000 oil and gas wells; 76 inspectors monitor these activities

(RRC, 2001). RRC regulates the petroleum industry, including

oilfield production, oil haulers, waste haulers, and waste liquid

injection facilities, as provided in the Texas Administrative Code,

5.0 Regulatory Analysis

 35Solid Waste Disposal Act of 1980, Section 3001(b)(2)(A).

 3653 FR 25446.

3758 FR 15284.

Protection Agency

Commission

In March 1993, EPA again refined the

definition to address the applicability

of the exemption to wastes generated

by crude oil reclaimers and other

processors, and storage and

transporter activities.
50

Title 16, Chapter 3. The scope of these rules includes permitting of

producers (shippers), haulers, and waste injection well operators;

monitoring production quantities; and ensuring environmental safety

(e.g., protecting groundwater). RRC also requires testing of production and disposal wells and associated equipment to prevent groundwater contamination.

RRC is responsible for regulating oil and gas production waste

management and disposal. Sections 3.9 and 3.46 of the Administrative Code contain State rules applicable to EPA Class II injection

wells. Hazardous oil and gas wastes are regulated by §3.98, “Standards for Management of Hazardous Oil and Gas Wastes.” RRC

does not regulate the transportation of material on public highways.

Although it requires a cargo manifest under §3.72, it does not require

characterization of hazards. However, DOT requires hazard classification on shipping papers (Section 5.4). At least one of the vacuum

trucks was carrying the required RRC manifest; the fire most likely

destroyed the second manifest.

RRC has authority to regulate resource conservation and safety under

the Texas Natural Resources Codes, provided in Rule 85.042(b):

When necessary, the commission shall make and enforce

rules either general in their nature or applicable to particular

fields for the prevention of actual waste of oil or operations

in the field dangerous to life or property.

RRC has exercised its authority applicable to safety only in cases

specifically related to hydrogen sulfide. There are no RRC regulations on worker safety related to the flammability hazard of waste

liquids or production fluids.

CSB concluded that neither the liquid waste hauler nor the disposal

facility emphasized the importance of minimizing the inadvertent

collection and disposal of crude oil or condensate when removing

BS&W from production storage tanks. RRC has not promulgated

specific regulations on controlling the inadvertent removal and

disposal of crude oil or condensate.

RRC has performed many routine inspections of environmental

compliance and reporting requirements at BLSR, with no significant

findings. On January 14, 2003, RRC inspected the facility because

of the fatal incident on the previous day and issued no adverse

findings.

RRC is responsible for regulating oil

and gas production waste

management and disposal.

[The RRC] cargo manifest [regulation]

does not require characterization of

hazards. However, DOT requires

hazard classification on shipping

papers.

There are no RRC regulations

on worker safety related to the

flammability hazard of waste liquids

or production fluids.

CSB concluded that neither the liquid

waste hauler nor the disposal facility

emphasized the importance of

minimizing the inadvertent collection

and disposal of crude oil or

condensate when removing BS&W

from production storage tanks.
51

 5.3 Occupational

OSHA has worker safety regulatory authority over oil production and

waste disposal facilities, as specified in 29 CFR 1910.1200, Hazard

Communication, which covers the identification of hazardous

chemicals and communicating information about the hazards to all

employees and other individuals who might handle the “chemical.”

Methods of communication include labeling and the use of MSDSs.

These OSHA regulations cover E&P waste liquids. Noble Energy

did not communicate the flammability hazard of BS&W to employees

or contractors handling this material at the well sites. The lack of

proper hazard communication to the T&L drivers resulted in mishandling of the OSHA Class 1B flammable liquid and, ultimately, to

release and ignition of the flammable vapor during offloading at

BLSR.

In addition to worker right-to-know, confined space entry, and hot

work, OSHA regulates workplace hazards involving the handling of

flammable liquids. 29 CFR 1910.106(a)(19) defines “Class I flammable liquid” as any liquid having a flashpoint below 100oF, including mixtures where more than 1 percent of the components have a

flashpoint below 100oF. None of the OSHA regulations are affected

by the RCRA Subtitle C exemption of E&P waste liquids, as discussed in Section 5.1.

CSB commissioned flammability tests on BS&W samples from the

two condensate tanks at the CJ Waller lease and from nine additional condensate tanks at six other lease wells. Ten of 11 BS&W

samples met the OSHA Class I flammability criteria. The sample

collection method used by CSB investigators ensured that the samples

contained only BS&W, with no condensate. Noble Energy conducted flammability tests on BS&W samples from the two condensate tanks at the Roberts lease; those results concluded that BS&W

was a Class I flammable liquid. Appendix A presents the flammability

test data results.

OSHA regulations require that facilities handling Class I flammable

liquids be designed to minimize the possibility of igniting flammable

vapors. Requirements apply to special electrical equipment and

spacing of equipment. BLSR did not apply these requirements to the

design and construction of equipment exposed to Class I flammable

liquids.

Safety and Health

Administration

Noble Energy did not communicate

the flammability hazard of BS&W to

employees or contractors . . .

The lack of proper hazard

communication to the T&L drivers

resulted in mishandling of the OSHA

Class 1B flammable liquid and,

ultimately, to release and ignition

of the flammable vapor

during offloading . . .

OSHA regulations require

that facilities handling Class I

flammable liquids be designed to

minimize the possibility of igniting

flammable vapors.

The OSHA investigation conducted

after the incident identified BLSR

management system deficiencies,

including the lack of an adequate

hazard communication program and

inadequate control of ignition sources.
52

The OSHA investigation conducted after the incident identified

BLSR management system deficiencies, including the lack of an

adequate hazard communication program and inadequate control of

ignition sources. Prior to the incident, OSHA had never audited the

facility.

5.4 U.S. Department

DOT has regulatory and enforcement authority for the transportation

of hazardous material on public highways. Regulations cover the safe

handling and operation of vehicles that transport hazardous material.

With flashpoints below 141°F, oil and condensate are DOT Hazard

Class 3 flammable liquids that must be transported in accordance

with DOT regulations for design, fabrication, maintenance, periodic

testing, and labeling of bulk transport tanks (49 CFR 173, 177, and

178).38 These regulations establish minimum training requirements for

drivers, limits on work hours, and record-keeping requirements. As

with OSHA, none of the DOT regulations are affected by the RCRA

Subtitle C exemption of E&P waste liquids, as discussed in Section

5.1.

CSB determined that BS&W removed from the CJ Waller and

Roberts leases and transported by the T&L vacuum trucks was a

DOT Hazard Class 3 flammable liquid. T&L did not transport these

waste liquids in accordance with DOT regulations. The shipping

paper prepared by the driver did not describe the hazardous (flammable) material, nor did it list the hazard class, identification number,

or packing group. In addition, the truck tanks did not conform to

applicable DOT regulations. The lack of proper identification of the

flammable liquid resulted in improper transport and mishandling at

the waste facility, which directly contributed to release and ignition of

the flammable vapor.

38These subchapters cover shipper and carrier responsibilities, such as proper classification and documenting of bulk transported materials, procedures for loading and unloading flammable liquids, and proper use of hazard placards to alert emergency responders

in the event of a vehicle accident.

of Transportation

With flashpoints below 141°F, oil

and condensate are DOT Hazard

Class 3 flammable liquids that must

be transported in accordance with

DOT regulations . . .

The lack of proper identification

of the flammable liquid resulted in

improper transport and mishandling

at the waste facility, which directly

contributed to release and ignition

of the flammable vapor.
53

6.1 Root 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.

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

offloading flammable liquid onto the mud disposal and washout pad.

 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.

6.2 Contributing

1. T&L management did not recognize that the process of

unloading BS&W from the storage tank is likely to increase its

flammability due to the unavoidable removal of highly flammable condensate along with BS&W. Although management

instructed drivers to avoid removing condensate, there was no

written procedure.

6.0 Root and Contributing Causes

Causes
54

2. 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 use available industry guidelines

(such as those contained in API Order No. G00004, Guidelines for Commercial Exploration and Production Waste

Management Facilities) to establish procedures for properly

identifying waste liquids and their associated flammability

hazards.

 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.

4. T&L and BLSR management failed to train their employees on

diesel engine overspeed 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 overspeed.
55

Noble Energy, Inc.

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. (2003-06-I-TX-R1)

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. (2003-06-I-TX-R2)

T&L Environmental

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. (2003-06-I-TX-R3)

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. (2003-06-I-TX-R4)

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. (2003-06-I-TX-R5)

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. (2003-06-I-TX-R6)

7.0 Recommendations

Services, Inc.
56

5. Conduct and document training for all personnel who handle

waste liquids, using languages or formats that are clearly understood by all affected personnel. (2003-06-I-TX-R7)

 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

overspeed caused by a flammable vapor atmosphere.

BLSR Operating, Ltd.

1. Develop a written Waste Acceptance Plan as recommended by

API Order No. G00004, Guidelines for Commercial Exploration

and Production Waste Management Facilities.

(2003-06-I-TX-R8)

 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. (2003-06-I-TX-R9)

 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.
57

3. Develop written procedures and provide training to employees

on unloading all flammable or potentially flammable E&P waste

liquids. (2003-06-I-TX-R10)

 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. (2003-06-I-TX-R11)

U.S. Department

Publish an information document for exploration and production

(E&P) industry employers (including producers/shippers/offerors,

motor carriers, and disposal facility operators) involved in the transportation of basic sediment and water (BS&W) and other E&P

waste liquids on public highways. (2003-06-I-TX-R12)

 Emphasize the importance of, and responsibility for, properly

classifying and identifying flammable waste liquids.

 Reference the Occupational Safety and Health Administration

(OSHA) requirements for obtaining material safety data sheets

(MSDS) from the shipper and the required content of DOT

shipping papers.

 Include specific reference to this CSB Investigation Report and

the American Petroleum Institute (API) recommended practices

cited in this report.

of Transportation (DOT)
58

Occupational Safety

Issue a Safety and Health Information Bulletin on the potential

flammability hazard associated with bulk transportation of oilfield

exploration and production (E&P) waste liquids.

(2003-06-I-TX-R13)

 Summarize OSHA requirements for proper hazard classification

by the shipper and for the use of material safety data sheets

(MSDS).

 Summarize U.S. Department of Transportation (DOT) requirements for proper hazard classification and manifesting of flammable liquids, approved container design, and periodic testing.

 Discuss safe handling to minimize the generation of flammable

vapor and to control ignition sources from vehicle-mounted

equipment and facility equipment.

 Discuss the need for the employer to provide all worker safety

information in languages or formats that are clearly understood

by all affected personnel.

 Summarize the requirements for proper labeling of storage tanks

to clearly identify the hazard of the contents to all employees

and contractors working at the well site.

Texas Railroad

1. Require that all permitted drillers and producers identify and

document (e.g., material safety data sheet [MSDS]) the potential

flammability hazard of exploration and production (E&P) waste

liquids. Provide the information to workers and contractors in

languages clearly understood by the recipients.

(2003-06-I-TX-R14)

2. Provide information (e.g., safety bulletin) to industry on the

potential flammability hazard associated with basic sediment and

water (BS&W) and other E&P waste liquids.

(2003-06-I-TX-R15)

 Waste liquids can contain sufficient hydrocarbons to be

classified as flammable liquids.

and Health Administration

(OSHA)

Commission (RRC)
59

 The waste liquid removal method can result in removing

significant quantities of flammable hydrocarbon product such

that the mixture in the transport container may require

classification as a flammable liquid under Occupational Safety

and Health Administration (OSHA) or U.S. Department of

Transportation (DOT) regulations.

American Petroleum

1. Revise API RP-2219, Safe Operation of Vacuum Trucks in

Petroleum Service, and API Order No. G00004, Guidelines for

Commercial Exploration and Production Waste Management

Facilities, to discuss the hazards of unloading potentially flammable or flammable liquids onto an open unloading area, such

as a concrete pad. Recommend other alternatives for minimizing vapor generation, such as unloading of flammable liquids

into a closed piping system. (2003-06-I-TX-R16)

2. Communicate the findings and recommendations of this report

to your membership. Emphasize that basic sediment and water

(BS&W) removed from crude oil and condensate storage tanks

requires special handling, in addition to compliance with Occupational Safety and Health Administration (OSHA) or U.S.

Department of Transportation (DOT) regulations, if it contains

sufficient hydrocarbons (either residual or mixed in during the

removal process) to be classified a flammable liquid as defined by

each regulation. (2003-06-I-TX-R17)

National Tank

Communicate the findings and recommendations of this report to

your membership. Emphasize emergency response to diesel engine

overspeed caused by exposure to flammable vapor atmospheres.

(2003-06-I-TX-R18)

Institute (API)

Truck Carriers, Inc.
60

By the

U.S. CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD

Carolyn W. Merritt

Chair

John S. Bresland

Member

Gerald V. Poje, Ph.D.

Member

Isadore Rosenthal, Ph.D.

Member

Andrea Kidd Taylor, Dr. P.H.

Member

September 17, 2003
61

Amerada Hess Corporation, 1998. Sweet Natural Gas Condensate,

Material Safety Data Sheet #15017, August 1998.

American Petroleum Institute (API), 2001. Guidelines for Commercial Exploration and Production Waste Management Facilities,

API Order No. G00004, March 2001.

API, 1999. Safe Operation of Vacuum Trucks in Petroleum Service,

API RP-2219, March 1999.

Brazoria County, Texas, 2003. Sheriff Incident Report #03010143,

January 22, 2003.

Chevron, 2001. Unleaded Gasoline, Material Safety Data Sheet

#3205, November 28, 2001.

Exxon Company, USA, 1999. Condensate, Material Safety Data

Sheet, Product Code 929335, March 22, 1999.

Lees, Frank P., 1996. Loss Prevention in the Chemical Industry,

Butterworth-Heinemann, Vol. 1, Chapter 15.1.

National Fire Protection Association (NFPA), 1999. Standard for

Automotive Fire Apparatus, NFPA 1901 A-8.2.4.1.

Phillips Petroleum Company, 1997. Sweet Natural Gas Condensate,

Material Safety Data Sheet, CAS #68919-39-1, October 31,

1997.

Reible, Danny D., and K. T Valkaraj, 1999. TCLP Characterization

of Exploration and Production Wastes in Louisiana, Louisiana

State University, March 1999.

Texas Railroad Commission (RRC), 2001. Waste Minimization in the

Oil Field, July 2001.

U.S. Army Corps of Engineers (USACE), 1998. Engineering and

Design: Removal of Underground Storage Tanks, Chapter 12,

Product Removal Procedures, EM 1110-1-4006, September 30,

1998.

U.S. Environmental Protection Agency (USEPA), 2000. Crude Oil

Tank Bottoms and Oily Debris, January 2000.

8.0 References
62
63

APPENDIX A: BS&W Hazard

Summary Table

3-1 Noble (CSB) X CJ Waller Lease samples 1/17/03, DOT

Class 3, OSHA Class IB

4-1 Noble (CSB) X CJ Waller Lease samples 1/16/03, DOT

Class 3, OSHA Class IB

B6 Gury Petroleum X Sample collected 2/11/03, DOT Class 3,

(CSB) OSHA Class IB

EPA-01 EPA , 2000 X DOT Class 3

EPA-02 EPA , 2000 X DOT Class 3

EPA-03 EPA , 2000 X DOT Class 3

EPA-04 EPA , 2000 X DOT Class 3

EPA-05 EPA , 2000 X DOT Class 3

EPA-06 EPA , 2000 X DOT Class 3

EPA-07 EPA , 2000 X DOT Class 3

EPA-08 EPA , 2000 X DOT Class 3

EPA-09 EPA , 2000 X DOT Class 3

EPA-10 EPA , 2000 X DOT Class 3

EPA-11 EPA , 2000 X DOT Class 3

EPA-12 EPA , 2000 X DOT Class 3

EPA-13 EPA , 2000 X DOT Class 3

EPA-14 EPA , 2000 X DOT Class 3

EPA-15 EPA , 2000 X DOT Class 3

EPA-16 EPA , 2000 X DOT Class 3

EPA-17 EPA , 2000 X DOT Class 3

EPA-18 EPA , 2000 X

EPA-19 EPA , 2000 X

EPA-20 EPA , 2000 X

EPA-21 EPA , 2000 X

EPA-23 EPA , 2000 X

EPA-22 EPA, 2000 X

 Sample Name Organization Flammable Hazard Comments

Yes No
64

 Sample Name Organization Flammable Hazard Comments

Yes No

EPA-24 EPA , 2000 X

EPA-25 EPA , 2000 X

EPA-26 EPA , 2000 X

EPA-27 EPA , 2000 X

EPA-28 EPA , 2000 X

EPA-29 EPA , 2000 X

EPA-30 EPA , 2000 X

EPA-31 EPA , 2000 X

EPA-32 EPA , 2000 X

G3 Noble (CSB) X Sample collected 2/11/03,

DOT Class 3, OSHA Class IB

G4 Noble (CSB) X Sample collected 2/11/03,

DOT Class 3, OSHA Class IB

Roberts 250 Noble X Samples collected 1/15/03,

DOT Class 3, OSHA Class IB

Roberts 251 Noble X Samples collected 1/15/03,

DOT Class 3. OSHA Class IB

RW8 Noble (CSB) X Sample collected 2/11/03,

DOT Class 3, OSHA Class IB

RW9 Noble (CSB) X Sample collected 2/11/03,

DOT Class 3, OSHA Class IB

S4 Noble (CSB) X Sample collected, 2/11/03,

DOT Class 3, OSHA Class IB

T1 Hillcorp Energy (CSB) X Oil well sample collected 2/11/03,

DOT Class 3, OSHA Class IB

T1B Hillcorp Energy (CSB) X Oil well sample collected 2/11/03,

DOT Class 3, OSHA Class IB

W5 Noble (CSB) X Tank contained in excess of

18 inches water

 TOTAL 29 16
65

APPENDIX B: Logic Diagram
66

Subtree A
67
68