Engineering Failure Analysis 45 (2014) 128–141

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Engineering Failure Analysis

journal homepage: www.elsevier .com/locate /engfai lanal

Root causes of fluid spills from earthmoving plant andequipment: Implications for reducing environmental and safetyimpacts

http://dx.doi.org/10.1016/j.engfailanal.2014.06.0111350-6307/� 2014 Elsevier Ltd. All rights reserved.

E-mail address: turlough.guerin@hotmail.comURL: http://au.linkedin.com/in/turloughguerin

Turlough GuerinThe Climate Alliance c/o 84 Fullbrook Dr., Sunbury, Victoria 3429, Australia

a r t i c l e i n f o

Article history:Received 12 February 2014Received in revised form 14 June 2014Accepted 25 June 2014Available online 9 July 2014

Keywords:Oil spillMachineryEquipmentRoot cause analysis (RCA)Hydraulic fluid

a b s t r a c t

A study was undertaken of plant and equipment spills across an earthworks contractor’soperation on a construction project in Western Australia owned and operated by an oiland gas company. The spilt product was predominately hydrocarbons (specifically hydrau-lic oil). During the 14-month timeline for the spill study, 86 individual spill events werereported. Loaders and excavators were the most likely items of plant to be involvedaccounting for approximately 40% of all spills. Only 30% (27 spills) were 20 L in volumeand greater. Hydraulic hoses, o-rings (within the hydraulic systems), and hydraulic hosecouplings (including failed crimped ends) represented 50% of the specific spill sources onthese machines. Of the 14 root cause descriptions, 4 of these could explain 60% of the spillincident causes. These were: ‘‘Equipment Parts Defective’’, ‘‘Incorrect Procedure Followed’’,‘‘Impact With an Object’’ and ‘‘Design Did Not Anticipate Conditions’’. Based on these con-clusions, recommendations for reducing spills are to increase rigour of inspection ofhydraulic hose fittings, increase the sharing of lessons learnt from spill events, and enhancethe reward and recognition of operators actively preventing and reducing spills.

� 2014 Elsevier Ltd. All rights reserved.

1. Introduction

1.1. Background

The construction of resource project infrastructure such as liquid natural gas (LNG) plants, requires extensive earthworks,deploying large fixed and mobile plant, under demanding project timelines, often operating in environmentally-sensitivelocations [1–5]. Petroleum hydrocarbon spills, which are a consequence of operating such heavy equipment, pose a signif-icant operational challenge for resource companies and contractors working on these projects partly because of their envi-ronmental impacts [1,6–8], partly because of approval and consent conditions which precludes such spillages, and to otherdirect and indirect costs [9–11]. Although spills from construction plant and equipment are refined products, i.e. lubricants,fuels, coolants, and not crude oil materials, they still pose a threat to wildlife and the environment, particularly as animalsmay see the spilt product and try to consume it, birds and other wildlife can be contaminated, and spilt product can lead toresidual soil and water contamination problems from their chemical constituents such as aromatic hydrocarbon and metals[1,12], and may also contribute to the creation of unsafe working conditions.

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1.2. Issues and concerns

Leaks and spills of petroleum hydrocarbon are a major concern in the upstream oil industry, from both a construction andoperational perspective [11,13–16]. The impact of leaks and spills on company (and/or operator) reportable HSE datademand special attention to control such incidents as an immediate measure but also to prevent its reoccurrence throughstrategic plans [10]. Further, lessons learnt from spill incidents need to be communicated to oil and gas operators and theircontractors more broadly across the upstream oil and gas industry to assist in reducing the incidence and severity of theseevents and there is evidence that this is not occurring to a sufficient degree on an national or international level [17,18].

1.3. Risk factors

Other researchers have reported on the causes of spills that occur during the operation of oil and gas facilities [2]. Alam[2] came to the conclusion that the majority (more then 90%) of these leaks and spills are due to one or combination of thepotential root causes such as: (i) aging facilities, (ii) equipment failure, (iii) construction defect, (iv) accidental damage, (v)defeat/bypassing protective system, (vi) ineffective quality control, (vii) operational deviation, (viii) design fault, (ix) blowout of oil well and (x) human error. Alam [2] also reported that the 22 most common reasons were shared across the com-pany in a specific Leak and Spill Prevention Campaign carried out for a month. The identification of the main causes and itspreventive actions resulted in enhanced awareness levels among workers [2].

The problem of leaking hoses, lines and their connectors has been around for as long as hydraulic systems themselves.Such leaks waste oil, pose a safety hazard and can compromise machine reliability, as well contributing to soil and ground-water efforts which could have otherwise been avoided, rectification of which consumes finite resources. It has beenreported that 370 million litres of oil leak from hydraulic equipment every year [19]. Sealing technologies in hydraulic sys-tems have advanced considerably over the past 30 years, but so too have hydraulic system operating pressures and responsetimes [19] and these can impact upon the sources and sizes of spills.

1.4. Regulatory requirements

There are numerous laws that regulate the control of pollution and wastes in Australia, including those from oil spills.Spills from plant and equipment have the potential to trigger these laws and regulations in relation to pollution of soil, waterand air. In Western Australia, the regulations that govern spills include the Western Australian Environment Protection Act(1986), The Dangerous Goods Safety Act (2004), Environmental Protection (Unauthorised Discharges) Regulations (2004),and the Environmental Protection (Controlled Waste) Regulations (2004) [20]. These regulations have an application acrossjurisdictions in Western Australia broadly, however, there are other more specific regulations, which impact localised, regio-nal areas, as well as client requirements that are not necessarily regulatory requirements, and which may apply to petroleumhydrocarbon spillages, which occur under specific construction developments and approvals projects. In addition to achiev-ing regulatory objectives, it is also important for companies in the oil and gas sector to aim to achieve best practise in all thedimensions of their activities [21].

2. Purpose and scope

The key objectives of this study were to describe the distribution of spills across plant and equipment types, sources androot causes of equipment fluid spills at an LNG construction site. The scope of the study was to analyse fluid spills from plantand equipment operated by the contractor that was undertaking the bulk earthworks, construction of the materials offload-ing facility (MOF), temporary construction (building) facilities, and preparation of the site for placement of the LNG trains onthe LNG plant construction site. It included all activities and personnel working directly for the contractor as well as asso-ciated subcontractors (engaged by the contractor) operating the rock crushing and screening plant, the civil works drillingrigs as well as the surface miner, and the subcontractors constructing the temporary building facilities, undertaking fencingand plumbing.

3. Method

3.1. General

In the current study, an analysis was undertaken of the nature and causes of heavy vehicles, equipment and plant spillsacross an LNG construction operation at a site in Western Australia. It describes the nature of fluid spill incidents occurringfrom operating 373 items of plant, where approximately 400 personnel were employed during a 24 h-a-day operation. Thestudy provided an analysis of plant and equipment fluid spill management during a 14-month period in the project, coveringthe main (earthworks) phase of the construction on the site. The period of the spill study was from February 2011 to April2012.

130 T. Guerin / Engineering Failure Analysis 45 (2014) 128–141

Spill report forms, completed by the contractor company, were supplied to the operator (or client), and copies were keptand analysed as part of the current study. Based on the information provided in the spill report forms and discussions withthe contractor workshop personnel, and using the client’s 5-why investigation process (an iterative question-asking tech-nique used to explore the cause-and-effect relationships underlying a particular problem) [22] a judgement was maderegarding the root cause of each spill incident. Investigation files were accessed in undertaking the analyses to confirm factsabout each spill event included within the study. These files included witness statements, photographs, evidence of reme-diation of any contamination, details of repairs, and failed part replacement, as well as the spill report form. Lubricant andfuel data, as well as all plant records including maintenance, were obtained from the contractor’s workshop records.

3.2. Data capture

Spill reports were completed for each spill event that occurred. The forms captured the information in Table 1. Reports,completed by the contractor company, were submitted to the operator within 24 h after each spill event. It is noted that spillevents were treated in the same way as any other environmental or safety incident on the site.

3.3. Root cause investigation

Each spill incident was investigated to determine the root cause or causes for the spill [23] within a period of one weekafter the event. Preselected root causes and root cause descriptions were provided as drop down boxes in the spill reportform (Appendix 1). The root causes were: Procedures and safe work practices, Design, Inspection and quality control, Train-ing and competency, Misunderstood verbal communication, Supervision, Risk management, Preventative maintenance/Repeat failure, No communication or not timely (communication), and Turnover needs improvement. It was anticipated thatthese proforma root causes would encapsulate the majority of the causes of spills. These pre-selected options were to facil-itate responses and outcomes from all spill incident events that were as consistent and comparable with each other as far aspractical, across all operations (globally) of both the contractor and operator. After investigation, the spill report was fina-lised to reflect the appropriate and agreed root causes and root cause descriptions. These were also checked by independentindividuals involved with the project (but not involved directly in the spill incident) to help ensure that the root cause wasconsistent with the available evidence on the individual incident or the spill file. The drop down (proforma) selections in thereport template, were developed over several decades of operating oil and gas facilities globally.

3.4. Plant and equipment repairs

Immediately after the spill was contained and remediated, workshop personnel were called to the spill location (if theplant was unable to be brought to the workshop). Repairs were undertaken to the plant and a discussion was held betweenthe author and the workshop supervisor during the shift in which the spill occurred to obtain a statement of the facts relatedto the spill which was used to complete the spill report form, and which was also used to inform the root cause analysis(investigation). After an initial estimate of spilt product volumes, where practical, a final estimate of volume spilt was deter-mined from the volume of product required to refill the plant and equipment to the manufacturer’s normal fill level. Allequipment was restocked with oil spill kit components after each spill event.

3.5. Spill remediation

After the spill event had been investigated, site visits and reviews had been completed by the incident investigation team,contamination resulting from the spill event was cleaned up. In the majority of incidents this was completed by removingthe contaminated soil by hand tools and disposing of the soil in hazardous waste bins on the site. Larger spill events (i.e.100 L and above) required the use of excavators to remove the contaminated soil and place it in these hazardous waste bins.Soil validation sampling was also conducted [24].

Table 1Spill capture data.a,b

Equipment Cause Location Remediation Fluid

Identificationnumber

Description (of thatmost likely)

General/specific receiving medium Recovered volume Description e.g. fuel, oil,hydraulic fluid

Make/Model Mechanisms of failure GPS co-ordinates Remedial action taken VolumeFailed component Severity of impact Location relative to other site works

(marked on a map)Replacement of spillequipment

Responsible worksupervisor

Date and time

a Some of the entries above were only able to be estimated at the time of reporting (within 24 h).b The majority of entries allowed a ‘‘drop down’’ option to assist in retaining consistency, enabling comparisons across spills events.

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3.6. Communication of spill incidents

Level 2 spill incidents, which were defined by the contractor as spills greater that 100 L onto land, were communicated toall operators as they returned to work after their rostered rest period (usually 6 days), at weekly tool box talks (addressingHSE risks), and in site-wide safety alerts (incident summaries) issued via email to all contractor personnel. In addition, every12 months, a practical demonstration was provided to all operators on how to respond to spills during construction activ-ities. All the spills were reported in the monthly report to the Operator and this information was made available to all con-tractor personnel (for their viewing in their own time). During the study period, a reward and recognition program wasinitiated that recognised operators that potentially avoided large spills through the early identification and reporting ofminor leaks on large plant items e.g. 125 t excavators, trucks and dozers.

4. Results and discussion

4.1. Site description

The LNG construction site was located on an island located approximately 80 km off the north-west coast of Western Aus-tralia, Australia. Much of the island is covered by Spinifex grasslands which provide important habitat for a variety of wildlifeincluding 24 endemic fauna species and a major turtle breeding ground. While the main feature of the island’s geography isthe undulating limestone uplands, the island is surrounded by a mixture of sandy beaches and rocky shores, low cliffs, dunes,salt flats and reefs. The natural topography is mostly flat with some grades exceeding 10–15% on the construction site wherehaul trucks were trafficking up and down (Fig. 1). The landscape is arid and the climate is usually hot and dry. Most of theannual rainfall occurs during the cyclone (wet) season between November and April, and amounts to approximately 320 mmper year. Because of its high biological conservation value, the island was declared a public reserve for flora and fauna andhas been classified as a ‘Class A’ Nature Reserve for the past 100 years.

4.2. Overview of spill incidents

The spilt product was predominately petroleum hydrocarbons (specifically hydraulic oil), and these events occurred onland only. During this time, 86 individual spill events were reported and recorded releasing an estimated total of 2774 L or2% of all oil used (dispensed into plant and equipment) into the environment during this period (Table 2). Given the projectwas in construction phase, none of the spills were a result of operation of the LNG plant.

4.3. Geographical distribution of spill incidents

The spills were predominantly in the main earthworks area of the site, i.e. the LNG plant area, where the future gas treat-ment plant was to be constructed. A small number of spills occurred on the MOF (marine offloading facility) which is approx-imately 2 km from the centre of the LNG plant site, which was also being constructed by the contractor. Although some plantand equipment items operated close to marine environments, no spills occurred on or in such waters as a result of the oper-ations of the contractor and its subcontractors during the study period.

4.4. Equipment fluid volumes and spill distribution

During the study period, there was a total of 373 plant items under the control of the contractor across the constructionarea, which could potentially contribute to spill incidents. Of these there were 167 items of heavy equipment i.e. P4.5 t. Theaverage monthly fuel consumption across all plant during the study period was approximately 950,000 L. Heavy equipmentused 800,000 L per month or 84% of the diesel burnt by the contractor. Fixed plant used 141,000 L or 15%, and light vehiclesused only 1%. Average diesel usage per month for the heavy equipment was 5000 L per plant item.

Fig. 1. The site construction footprint on which the study was undertaken showing earthworks. Note: The MOF is off the top of this picture and the highestgradients on the site are toward the bottom left of the picture.

Table 2A summary of the largest spill events by volume occurring over the study period.

Volume Producta Description of spill event Dateoccurred

Type ofequipment

Source of spill Root cause description

700 Hydraulicfluid

An excavator was operating in LNG site when the main pressure hose from hydraulic pump to control valveruptured, releasing approximately 700 l of hydraulic fluid

9/05/2011

Excavator Hydraulic hose Equipment partsdefective

279 Hydraulicfluid

An excavator operator was pushing materials with bucket, when a rock fell down from the upper level of theexcavation hitting the ram hose pipe and joints causing damage and hydraulic fluid spill (279 L) on land

25/08/2011

Excavator Hydraulic line& hose

Inadequate processhazard analysis

140 Hydraulicfluid

A WA600 Loader was carrying material out of sbeing loaded with Sub-base material from behind rock sizerplant when excavator operator noticed hydraulic fluid leakub-base (SB) stockpile when a 140 L oil lead wasidentified from a compromised blanking disc on the main hydraulic pump

24/03/2011

Loader Hydraulicpump

Design did notanticipate conditions

135 Hydraulicfluid

785–5 Dump Truck was being loaded with Sub-base material from behind rock sizer plant when excavatoroperator noticed hydraulic fluid leak. 135 L of hydraulic fluid was released to land from a split O-ring on mainhydraulic feed line from control valve to hydraulic pump

13/11/2011

Haul truck O-ring Damage from lack ofuse

125 Hydraulicfluid

An excavator was operating under normal operations (placing concrete blocks on the MOF). Approximately125 L of hydraulic fluid spilled to land

24/07/2011

Excavator Hydraulic hose Equipment partsdefective

116 Hydraulicfluid

Approximately 116 L of hydraulic fluid spill onto land resulted from ruptured hydraulic pump outlet pressurehose on PC1250 excavator whilst slewing to pick up concrete blocks on the MOF

25/08/2011

Excavator Hydraulic hose Equipment partsdefective

101 Hydraulicfluid

An excavator was operating in the LNG site when a 101 L hydraulic fluid spill resulted from left bucket RAMhose failure

26/08/2011

Excavator Hydraulic hose Mistake or mental slip

100 Hydraulicfluid

A WA600 loader burst a hydraulic hose while loading material out of the LNG site, spilling approximately 100 Lof fluid to land

7/08/2011

Loader Hydraulicpump

Design did notanticipate conditions

90 Hydraulicfluid

An articulated dump truck was carting sub-base material to the LNG site when operator noticed an oil leak.Approximately 90 L of hydraulic fluid spilled because of a burst hydraulic hoist cylinder hose

27/07/2011

Haul truck Hydraulic hose Equipment partsdefective

80 Hydraulicfluid

An excavator was loading material to run of mine (ROM) 3 when an 80 L oil leak was identified from a loosemetal pipeline from the hydraulic pump to the control valve

15/04/2011

Excavator Hydraulic line No inspection

70 Diesel A 140H grader was grading the office car park when a 70 L diesel fuel leak was identified from a torn ‘quick fill’fuel hose

3/03/2011

Grader Fuel hose Design did notanticipate conditions

70 Hydraulicfluid

A 1250 excavator was placing concrete blocks on MOF when a hydraulic hose burst releasing 70 L of hydraulicfluid onto land. Inner lining of hose was hard and brittle likely to be a result of wear and tear

19/12/2011

Excavator Hydraulic hose No preventativemaintenance forequipment

50 Diesel A service operator was refuelling a 465 dump truck on the go-line (near workshop) when approximately 50 L offuel overflowed from the breather

15/04/2011

Haul truck Fuel tank No learning objective

46 Hydraulicfluid

A surface miner was operating in LNG plant site when a broken steering cylinder mount caused the supplyhydraulic hose fitting to snap resulting in approximately 46 L of hydraulic fluid spilling to the ground

27/08/2011

Surfaceminer

Hydraulic hose Equipment partsdefective

40 Hydraulicfluid

A 785 dump truck was hauling material for placement on the materials off-loading facility (MOF) when an oilleak was identified. Approximately 40 L of hydraulic fluid leaked to land. An o-ring split as a result of thehydraulic pump overheating. Overheating occurred because hoist lever was in hold position when travelling.Hoist lever is to be in the float position (not the hold position) to allow oil to cycle through cooler

23/07/2011

Haul truck O-ring Understanding needsimprovement

40 Hydraulicfluid

A D10 dozer was operating on main stockpile when the hydraulic line failed due to temporary welding repair topipe ferrule. Forty litres of hydraulic fluid was required to replenish contents of hydraulic oil tank and enablethe dozer to be moved to lower ground for further maintenance

20/01/2012

Dozer Hydraulic line Replacement part notavailable

34 Hydraulicfluid

An excavator was operating in LNG area when a hydraulic hose burst releasing 34 L of fluid onto land. Theruptured case drain hydraulic hose under cabin could not be observed at pre-starts as several guards have to beremoved to inspect

11/09/2011

Excavator Hydraulic hose No inspection

30 Hydraulicfluid

A WA600 loader was travelling along the main haul Rd to run of mine (ROM) stockpiles when the steering o-ring failed. It released 30 L of hydraulic fluid onto land

22/09/2011

Loader O-ring Equipment partsdefective

30 Hydraulicfluid

Grader was travelling to the Go-line along the main haul Rd past rock crushing operations to park up at the endof the day when an oil leak was noticed. Operator shut down machine, and an oil leak (30 L) was identified fromtandem drive drain box. Incorrect bolts were used to repair tandem drive drain housing in May 2011

7/11/2011

Grader Hydraulic tank Accepted to deviatefrom procedure

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30 Diesel A loader was working when the operator reversed over a rock damaging the fitting used to drain the fuel tank.The fitting snapped resulting in a diesel leak of approximately 30 L onto land

27/11/2011

Loader Fuel tank Impact with an object

30 Hydraulicfluid

A dozer was operating on the spoil dump when a rock pushed up through the dozer’s ripper box causingdamage to hydraulic hoses. An oil spill (30 L) resulted from hydraulic fluid leaking from the damaged hydraulichoses

16/12/2011

Dozer Hydraulic hose Impact with an object

25 Hydraulicfluid

A surface miner was operating in LNG area when an 25 L oil leak was identified from a piggy back hydraulicpump that had come loose from the main hydraulic pump

26/04/2011

Surfaceminer

Hydraulicpump

Design did notanticipate conditions

20 Diesel A WA 600 loader was operating at rock crusher when the fuel tank drainage valve was knocked off by runningover large rock releasing 20 L of diesel

9/02/2011

Loader Fuel tank Incorrect procedurefollowed

20 Degreaser A surface miner was being washed down prior to maintenance 12/02/2011

Surfaceminer

Pre-maintenancewash-down

Incorrect procedurefollowed

20 Hydraulicfluid

A D10 dozer was ripping when a ripper hydraulic hose failed releasing 20 L of hydraulic fluid onto land. Twohoses were rubbing together and one has worn through

30/03/2011

Dozer Hydraulic hose No preventativemaintenance forequipment

20 Hydraulicfluid

A surface miner was operating in LNG plant area when the hydraulic hose to gear change mechanism failed (asit wore against another structure) releasing approximately 20 L onto land

6/09/2011

Surfaceminer

Hydraulic hose Design did notanticipate conditions

20 Hydraulicfluid

A WA 600 loader was pushing soil into a stockpile when the hydraulic hose connected to the boom hydraulicram failed. No spilt hydraulic oil was observed on the ground but there was evidence of product sprayed ontoback of bucket. Twenty litres of product was required to replenish contents of its hydraulic oil tank

20/01/2012

Loader Hydraulic hose Equipment partsdefective

a Hydraulic fluid was a commercial grade synthetic product readily available in Western Australia.

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134 T. Guerin / Engineering Failure Analysis 45 (2014) 128–141

Two items of heavy plant, the surface miner and one of the 125 t excavators, used 8% of all diesel consumed. These dataindicated that the majority of energy used at the construction site was expended by a small number of high-powered equip-ment, moving relatively large volumes of disturbed and undisturbed soil and rock. It is therefore also this equipment mostlikely to be under the highest mechanical stress and more likely to be prone to fluid leak and spill incidents.

Oil consumption (i.e. plant refill/top-up volumes) across the plant fleet was 5000–10,000 L per month. The approximatevolume of hydraulic oil in the entire contractor’s plant was 25,000 L at any one time (as determined from the manufacturer’sspecifications for each plant item).

There were a total of 20 different types of plant and equipment involved in the spill incidents (Fig. 2) which were obtainedfrom the spill report forms. Of these, 8 types accounted for 80% of these incidents. These 8 types were, in decreasing fre-quency of involvement, as follows: loaders, excavators, haul trucks, a surface miner, water carts (i.e. trucks), graders, dozers,and a drill rig. Loaders and excavators were the most likely items of plant to be involved in spill incidents accounting forapproximately 40%. A frequency distribution of the spills across the plant types is provided in Table 3. The most frequentnumber of spills occurred on loaders (17), excavator (16) and haul trucks (8).

During the course of the study, the spill distribution profile changed (Fig. 3). Approximately half way through the study, inmid 2011, the project experienced a large 700 L spill. The majority of spills after this time were more frequent than the pre-vious period, as shown by the more intense clustering of data points in the second half of the study (Fig. 3). An explanationfor this increase in intensity of spills may be explained by the increased intensity of the earthworks on the site as the depthof excavations and movement of overburden increased.

4.5. Description of largest spill incidents

The proportion of all spills that were hydraulic spills P100 L, was only 9.3% in this study. The largest proportion of spillswas from hydraulic spills 6100 L (classified as Level 2 spills). The highest volume spills were predominantly spills involvinghydraulic oil, with 5 represented by diesel and degreaser. The majority of these spills involved a hydraulic hose and/or itsfittings failing. All the recorded spills were from operational machines indicating that spills are unlikely to occur passivelywhile machines are in lay down or otherwise not in operation. The relatively small proportion of large spills in the studyreflect training provided on the project during toolbox talks and ‘‘mock’’ spill events which were conducted by the author,as well as heightened awareness given to spill reporting and mitigation.

4.6. Products spilt and specific spill sources

The main product released across all the 86 spill incidents was hydraulic oil. Hydraulic oil was present in 74% of the 86incidents, diesel 16%, engine oil 7% and the remaining 2% was degreaser and brake fluid. Only 3 additional non-hydrocarbonproduct spills were experienced during the study period [and which were excluded from the analysis]: 1. 10 L of coolantfrom an excavator; 2. 200 L of concrete accelerant (containing mild acid) from the shotcreting operations (i.e. where concreteis sprayed onto metal or other structural supports); and 3. Approximately 300 L of diluted toilet waste from a failed cistern ina temporary building on the construction site. These events are not discussed further here.

The main sources of spills were from hydraulic system components (Fig. 4). The specific sources of spills, in decreasingorder of frequency, were as follows: hydraulic hoses, hydraulic hose couplings, hydraulic lines (i.e. metal), hydraulic pumps,hydraulic tanks, o-rings (on hydraulic systems), fuel tanks, oil filters, and refuelling nozzles and fuel hoses. This list of

Fig. 2. Distribution of spill incidents across type of plant and equipment.

Table 3Spill frequency across equipment types.

Frequency Type of equipment

17 Loader16 Excavator8 Haul truck7 Surface miner6 Water cart5 Grader4 Dozer3 Drill rig2 Bobcat telehandler2 Crane2 Pad foot roller2 Service truck2 Various1 Bobcat1 Cone crusher1 Drum roller1 Excavator arm1 Generator set1 Rock breaker attachment1 Stressing jack1 Trencher

Fig. 3. Distribution of spill incidents by volume.

Fig. 4. Source of spills from equipment.

T. Guerin / Engineering Failure Analysis 45 (2014) 128–141 135

136 T. Guerin / Engineering Failure Analysis 45 (2014) 128–141

components represented 80% of all spill sources. The subset of hydraulic hoses, o-rings (within the hydraulic system), andhydraulic hose couplings represented 50% of the spill sources.

4.7. Root cause descriptions

The proforma root causes (described in the Method) were ascribed to each of the spill events. Of the 14 root causedescriptions ascribed to all 86 events, 4 could explain 60% of the spill incident causes. These were: ‘‘Equipment Parts Defec-tive’’, ‘‘Incorrect Procedure Followed’’, ‘‘Impact With an Object’’ and ‘‘Design Did Not Anticipate Conditions’’. Of these,‘‘Equipment Parts Defective’’ accounted for the largest proportion of spills at 42% of the incident causes (Fig. 5). These rootcauses were typically associated with failures in the hydraulic system such as connectors and o-rings (Fig. 6). In the incidentshown in Fig. 6, the failed component was not able to be directly observed during equipment pre-starts, or routine mainte-nance, and therefore was a problematic root cause as it is difficult to predict such sources of spills.

These findings suggest that at least a portion of the spill incidents could be readily controlled or reduced. For example, thecause ‘‘Incorrect Procedures Followed’’ can be addressed by increasing the effectiveness of training particularly in the useand handling of heavy equipment. The cause ‘‘Impacting With an Object’’ is also able to be reduced by targeting safer han-dling and use of the heavy equipment, reducing collisions and accidents. The cause, ‘‘Equipment Parts Defective’’, is less read-ily controlled. This is because all vulnerable components, which include the hydraulic systems of the heavy equipment of theplant in the current study, would have to be assessed and tested for faulty parts which is not a practical option for operationssuch as this given that many faults in hydraulic systems are not visible to operators (doing pre-start checks) or to mainte-nance personnel during scheduled maintenance or repairs (Fig. 6). The cause ‘‘Design Did Not Anticipate Conditions’’, mayhave some limited value in spill prevention in retrospect, where the spill incident details could be helpful for the equipmentmanufacturers in designing plant for the actual conditions experienced while constructing the LNG plant. All of the top fourroot causes were also within the cluster of the major root causes reported in Alam’s [2] study of causes of oil spills in theupstream oil and gas industry. Because of the proforma root causes and root cause descriptions used in the current study,it is difficult to make comparisons with the other spill studies such as Casey’s [19] however a commonly identified root causebetween studies is the quality (condition) of hydraulic hose/line connectors.

4.8. Equipment hours at time of spills

Total hours on equipment at time of spill, and equipment age, was also investigated as a further root cause for spill inci-dents. A correlation analysis showed that there was no correlation between the occurrence of an incident and size of spill andplant and equipment hours. The regression co-efficient between the size of spills and the equipment age at time of spill was0.03. This finding was unexpected as equipment vulnerability to spills was predicted to be higher with a larger engine hourreading at time of spill (than one that is lower).

In reviewing the spill events from a volume perspective, of the 16 largest spills, which ranged from 20 to 700 L, 50% wereattributed to two items of plant: 2 � 125 t excavators. The reason for the largest spills occurring from events associated with

Fig. 5. Root cause description.

Fig. 6. An example of a failed o-ring from an hydraulic pump supply hose on plant from site. Note: This spill (40 L) was not able to be readily predicted as thefailed o-ring was the cause and was not able to be viewed in routine inspections and is only replaced on set scheduled maintenance periods. O-ringreplacement must follow the manufacturer’s recommendations to help minimise spills from this source.

T. Guerin / Engineering Failure Analysis 45 (2014) 128–141 137

these plant items was that the hydraulic oil capacity on the 125 t excavators was 970 L (as reported in the manufacturer’smanual), as well as the increased stress and higher workloads experienced by these plant items.

4.9. Comparison with other construction sites

4.9.1. From same contractorAn analysis of other sites where the contractor was undertaking earthworks in Western Australia, was conducted. During

the 10 year period leading up to the current study, a study of all the other sites that the contractor was operating in the Wes-tern Australia area demonstrated that the current site (operating for 14 months) accounted for approximately 25% of allenvironmental incidents. Further, more than 50% of the environmental incidents, in the Western Australia business unit(of the contractor), occurred on the current site during the study reporting period. This was at least partly due to theincreased incidence of reporting by operators which has been driven by a strong corporate culture to enhance transparency,and from the stringent reporting requirements of the operator (i.e. oil and gas company owner of the site).

From an Australia-wide perspective, the contractor’s spill data revealed that hydraulic leaks and fuel/oil spills were themost common environmental incident types during the year preceding the current study. This confirmed the importanceof understanding spill mechanisms from their plant and equipment. The majority of these hydraulic leaks and fuel/oilsspills were classified as ‘‘once-off’’ incidents (83%), with the common theme of unavoidable or unpredictable equipmentfailure associated with the incident cause. Given these strong historical trends, it is likely that hydraulic leaks and fuel/oilspills will continue to be a main source of environmental incidents for ongoing and future project operations for the con-tractor. To reduce the number of these incidents from occurring and to minimise associated impacts, the contractor devel-oped communications that highlight the following lessons: Equipment is to be regularly inspected, maintained andoperated within manufacturer’s recommended specifications; Appropriate work procedures have been developed andare being implemented for activities that have the potential to cause leaks/spills (e.g. equipment refuelling, equipmentdetachment, unloading activities etc.); Spill kits are to be maintained and located near current work activities that havethe potential to result in leaks/spill, particularly for hydraulic powered machinery operating within close vicinity towaterways and drains; Employees have undergone adequate training to control, contain and clean up hydraulic/fuel/oilspills.

Even with this information communicated across the contractor’s projects nationally, including the current site through-out and up to the end of the study period, spill events still occurred on the construction site in the current study. Furtherchecking of plant operator’s understanding of how to review plant and equipment items susceptible to failure, may berequired through enhanced and focused training. Others [2] have reported on an operation that, during a spill awareness

138 T. Guerin / Engineering Failure Analysis 45 (2014) 128–141

campaign, each day a brief description, preventive action for an individual cause of leak and spill was circulated throughoutthe operational facility. The campaign was also supported with presentations, posters, leaflets, a quiz program, mementoesand motivational schemes; all of which were designed to increase awareness of spills and their causes. The impact of theseinterventions was, however, not measured.

4.9.2. Confidential studiesOther operators and contractors operating similar plant and equipment as that deployed on the current site (although not

LNG construction or other construction sites), have also analysed the distribution and causes of oil spills from operating plantand equipment. One such study from North America at a remediation site deploying excavators, trucks, dozers and relatedplant, revealed that hydraulic system leaks were the primary cause of oil spills and leaks [25]. Further, these were shown tobe linked to failed hose connectors and worn hoses (Table 4). The findings from this unpublished study distilled lessons onaspects of the plant and equipment to focus on to assist in reduced hydraulic fluid leaks and spills (Table 5). Other research-ers outside the oil and gas sector have prepared guides to assist industry operators to reduce spills [26]. From a 10 year studyof spills in a city in Canada, researchers found that human error and equipment failure are the main reasons of spills [27].

Table 4Causes of hydraulic oil spills from North America with similar plant & equipment on a contaminated soil remediation site.

Plant & equipment item Event type Issue Determined cause

Excavator Near Miss Hose Leak Pinhole at crimpExcavator Spill Hose Failure Defective crimpDozer Near Miss Hose Leak Pinhole at crimpDrill rig Near Miss Cylinder Leak ‘‘Bad Seal’’Drill rig Spill Hose Failure Outer cover failure rupture through reinforcementExcavator Spill Hose Leak Loose fittingExcavator Spill Hose Failure Outer cover failure, rupture through reinforcementSweeper Spill Hose Leak Tension/Twist, reinforcement failure30 ton truck Spill Hose Leak Pinhole leak, outer cover wear40 ton truck Spill Hose Leak Pinhole at crimp, reinforcement failure40 ton truck Near Miss Hose Leak Bubble under outer cover30 ton truck Near Miss Hose Leak Leak at crimp30 ton truck Near Miss Hose dampness Out cover, pinhole beneathExcavator Spill Hose Failure Outer cover/reinforcement degradedExcavator Stop Work Hose Worn Precaution, opposing hose had failedExcavator Near Miss Hose Damage Rental shear with bad hoses from vendor/supplierDozer Near Miss Hose Damage Rental dozer with bad hoses from vendor/supplierGeoprobe Rig Stop Work Hose Damaged Pre-entry inspection identified cracked/weathered hoseGeoprobe Rig Spill Hose Leak Pinhole leak on outer bend of hose

Notes: Data not previously published. Spill volume, date, product type, event description or cause not provided.

Table 5Lessons learnt from operators and contractors in North America with similar plant & equipment on a contaminated soil remediation site.

Issue Description

Focus on the crimp ends Hose failures and leaks at the connectors were a common occurrenceSince connection is fixed and hose moves, this location is most susceptible to twist/torsion

Outer cover appears to be the firstto go

The outer cover being loose or damaged was common to most failuresOuter cover issue cannot always be seen, may need to feel hose surface to detect

Hoses in high-motion locations arehighest risk

More than 80% of hydraulic Hose failures were high motion/rotation hosesThe evaluated hoses that showed signs of pre-failure were all higher motion location hosesThe crimp ends of high-motion hoses were observed to have outer cover loosening or outer reinforcementloosening

Manufacturer’s advice should beheeded

Hydraulic Fluid monitoring can only detect inner tube failure issuesThe age of the hose is not necessarily related to its performance or likelihood of failure. However there is likelyan age at which the probability of failure increases but an assessment of this requires more dataThere is limited opportunity for visual assessment to predict a hose failureTwisting or misalignment absolutely accelerate hose wear and risk for failure

Inspection frequency andthoroughness matters

Near-miss identification of leaking or troubled hoses have greatly increased at site since vendor-provided HoseInspection Training classFor the near-miss hoses that were found and replaced all exhibited signs of outer cover and/or reinforcementfailureInspections are finding hoses in hard-to-see locations with signs of issues

Notes: This data has not been previously published.

Table 6Lessons learnt from the current study.

Issue Description of learning

Failed hoses and hose fittings aremajor source of spills

Improve the quality of and focus applied when conducting machine pre-starts. Anticipate heavy vehicletypes and applications where spills are likely to be most prevalent

Enhance communication Ensure operators of plant are informed of all spills during return to work briefings, pre-starts and toolboxtalksAdvise heavy vehicle and equipment vendors of areas where common leaks and spills arise

Recommendations for adoption Engage heavy vehicle and equipment vendors on spill reduction initiatives and spill prevention strategiesIntroduce KPIs to focus on leaks, seeps and weeps (not reporting spills only)Regulatory bodies to drive pollution prevention and operational environmental protection licences thatlegislate preventative actions for spill management from plant and equipment

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5. Conclusions

5.1. General

The findings provide an analysis of spills across a major construction site, giving insights into probable causes for equip-ment fluid spills from the plant and equipment, and that are applicable to construction projects more broadly.

Hydraulic oil spills from failed hydraulic hoses and their fittings are the most common sources of spills, representing 80%of all spill sources confirming other researcher’s findings. The three generic types of plant and equipment most likely to beinvolved in a spill event are loaders, excavators, and haul trucks contributing to 49% of heavy plant involved in spills.

In terms of the root causes, approximately 50% of spills were from defective equipment parts and manufacturer’s designsnot anticipating the conditions experienced by operators using the equipment. These causes are considered to be difficult tocontrol and reduce (by contractors on site) and were not examined further in this study. A smaller proportion (approxi-mately 25%) of root causes were identified as incorrect procedures followed, equipment impacting with other objects, noinspection, operators accepting to deviate from procedure, mistakes (or ‘‘mental slips’’), inadequate process hazard analysis,and operator’s understanding of equipment needs improvement. These root causes on the other hand were considered to bewithin the control of the contractor company on the site and specifically, its operators, the workshop/field service mainte-nance team, and field supervisors. Table 6 summarises the lessons learnt from the current study.

5.2. Recommendations

Based on the findings from the current study, the following recommendations are offered with the aim of reducing spillsfrom plant and equipment on similar construction projects. For operators and contractors, these are: 1. Improve the qualityand rigour of visual inspections of hydraulic hose and hydraulic hose fitting (crimpings), on all heavy equipment particularlyduring pre-start checks and ensure effective training in this activity is provided; 2. Increase the sharing of lessons learnt fromspill events and the corrective actions taken across the operator (earthworks and workshop) workforce using pre-start dis-cussions and toolbox talks (not just for large ie P100 L spills and doing this during return to work debriefs); 3. Develop leadindicators that assist in the early detection of oil spills; 4. Enhance reward and recognition program for plant operators iden-tifying equipment components at risk of causing a spill. This is to be available to plant operators who have successfullyattended and completed the training in the first recommendation (above); for regulators, 5. Encourage adoption of preven-tative measures that drive behaviours that will eliminate or reduce the size of spills; for researchers, 6. Undertake statisticalstudies on the benefits of using premium hoses and fittings.

6. Further research

An opportunity for further research would be to further communicate the findings from the current study with vendors ofthe equipment assessed in the study to determine the merit of integrating design changes to alleviate spills from new equip-ment. The author has previously described the critical role that petroleum hydrocarbon suppliers to the resource industrycan play in enabling the resource sector to achieve its goals for sustainable development, by reducing environmental impact[28]. Engagement with plant and equipment suppliers by operators (i.e. oil companies) and or their civil contractors on spillprevention would be a logical next step.

Appendix A

See Appendix 1.

Appendix 1Proforma root causes of fluid spills used in investigations on the LNG construction site.a

Root cause Root cause descriptionb

Procedures and safe work practices Accepted to deviate from work routineLack of job oversightMistake or mental slipNone exists or availableNot complete or accurateNot enforced, audited, or inspectedNot trained on procedureOther priorities conflictedRisk of not following not understoodWillful deviation

Design Design standards inadequate or not usedDid not anticipate the conditionsDid not consider human factorsInadequate reviewInherent safety design not incorporated

Inspection and quality control No inspectionQuality control needs improvementHold point not performedInspection not requiredNo hold pointForeign material exclusion during work needs improvementInspection instructions needs improvementInspection technique needs improvement

Training and competency No trainingUnderstanding needs ImprovementDecided not to trainMissed required trainingNo learning objectiveTask not analysedContinuing training needs improvementInstruction needs improvementLearning objective needs improvementLesson plan needs improvementPractice/repetition needs improvementTesting needs improvement

Misunderstood verbal communication Long messageNoisy environmentRepeat back not usedStandard terminology needs improvementStandard terminology not used

Supervision PreparationSelection of workerSupervision during workFall protection needs improvementLock out/tag out needs improvementNo preparationPre-job briefing needs improvementScheduling needs improvementWalk-through needs improvementWork package/permit needs improvementFatiguedNot qualifiedSubstance abuseTeam selection needs improvementsUpsetInadequate job hazard/safety analysis

Risk management Inadequate process hazard analysisIndividual snap decision (quick decision made without assessing the risk)

Preventative maintenance/repeat failure Equipment parts defectivePreventative/predictive maintenance/not preventative maintenance for equipment

No communication or not timely Preventative/predictive maintenance/preventative maintenance for equipment needs improvementCommunication system needs improvementLate communication

Turnover needs improvement No standard turnover processTurnover process needs improvementTurnover process not usedTurnover less than adequate

a All of these root causes were available as drop down options in the spill report forms. Individuals completing the forms were required to use theprovided proforma options which also included ‘‘not applicable’’ (not listed in this table).

b Additional root causes with no further descriptions (to tabulate): Contractor safety, Communications, Human factors, Management of change, Incidentand near miss investigation, Emergency response, Natural phenomenon, Auditing, Leadership Accountability, and Pre start up safety review.

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