United States EPA 744­S­08­001 

Environmental Protection June 2008 Agency 

Wire and Cable Insulation and 

Jacketing: Life­Cycle Assessments
 

for Selected Applications 

Summary 
       

    

   

EPA 744­S­08­001

United States June 2008

Environmental Protection 

Agency 

Wire and Cable Insulation and 

Jacketing: Life­Cycle Assessments
 

for Selected Applications 

Summary 

This summary document is based on information presented in the EPA Design for the

Environment project report, Wire and Cable Insulation and Jacketing:  Life­Cycle

Assessments for Selected Applications.  Some information in the life­cycle

assessment report was provided by individual technology vendors and has not been

independently corroborated by EPA.  The identification of specific products or

processes in this document is not intended to represent an endorsement by EPA or

the U.S. Government.  This summary document has not been through a formal

external peer review process.
AC K N O W L E D G E M E N T S

This life­cycle assessment (LCA) summary was prepared for the U.S.  Environmental

Protection Agency’s (EPA’s) Design for the Environment (DfE) Wire and Cable

Partnership by Abt Associates Inc., under contract #68­W02­077.  This document is

based primarily on the full project report, Wire and Cable Insulation and Jacketing:

Life­Cycle Assessments for Selected Applications, prepared by Maria Leet Socolof, 

Jay Smith, David Cooper, and Shanika Amarakoon, under funding from the U.S.

Environmental Protection Agency’s DfE Program in the Economics, Exposure, and

Technology Division (EETD) of the Office of Pollution Prevention and Toxics (OPPT).

This LCA study was conducted as part of the DfE Wire and Cable Partnership, under

the direction of the project’s Core Group members, including Kathy Hart, Project CoChair, U.S.  EPA OPPT, DfE Branch; Liz Harriman, Project Co­Chair, Toxics Use

Reduction Institute, University of Massachusetts Lowell; Maria Leet Socolof, David

Cooper, Jay Smith, Shanika Amarakoon, Christopher Guyol, and Brian Segal, Abt

Associates Inc.; Susan Landry, Albemarle Corporation; Dave Kiddoo, Gary Nedelman,

and Troy Brantley, AlphaGary Corporation; Charlie Glew, Cable Components Group,

LLC; Joe Daversa, Chemson, Inc.; Rob Wessels, CommScope; Ralph Werling and Gary

Stanitis, Daikin America, Inc.; Stacy Cashin and James Hoover, DuPont; Fred Dawson,

DuPont Canada; Brenda Hollo and Paul Kroushl, Ferro Corporation; Dr.  Henry Harris,

Georgia Gulf; Akshay Trivedi, Judd Wire; Richard Shine, Manitoba Corporation; Richard

LaLumondier, National Electrical Manufacturers Association (NEMA); Tim Greiner,

Pure Strategies, Inc.; J. Brian McDonald, SGS–US Testing–CTS; Melissa Hockstad,

Society of the Plastics Industry (SPI); Paul Sims, Southwire Company; Stefan Richter,

Sud­Chemie, Inc; Dr. Jim Tyler, Superior Essex; Mike Patel, Chuck Hoover, and David

Yopak, Teknor Apex Company; Scott MacLeod and Steve Galan, Underwriters

Laboratories; H.J. (Bud) Hall and Frank Borrelli, Vinyl Institute of the American Plastics

Council.

The authors gratefully acknowledge the contributions of James Murphy and of the late

J. Vincent Nabholz of EPA’s Risk Assessment Division, OPPT. Their assistance in

reviewing and providing health and environmental toxicity information for the project

was greatly appreciated.

The authors would like to acknowledge the outstanding contributions of the Abt

Associates staff who assisted the authors, including Alice Tome for her technical

quality review; and Van Smith, Emily Connor, Kavita Macleod, and Sue Greco for their

technical support.
CO N T E N T S
 

Introduction.............................................................................................................1
 

Question 1: 

What is a life­cycle assessment?.....................................................................2
 

Question 2: 

Which wire and cable products were investigated during the project? ........4
 

Question 3:
 

How were environmental and health impacts evaluated?.............................6
 

Question 4: 

How was uncertainty in the wire and cable life cycle addressed?..............10
 

Question 5:
 

What are the health and environmental impacts of baseline, lead­free, and
 

zero­halogen CMR cables, and what drives the impacts?...........................12
 

Question 6:
 

What are the health and environmental impacts of baseline and lead­free
 

CMP cables, and what drives the impacts?..................................................20
 

Question 7:
 

What are the health and environmental impacts of baseline and lead­free
 

NM­B cables, and what drives the impacts? ................................................27
 

Question 8
 

Overall, where are the greatest potential health and environmental
 

impacts? .........................................................................................................33
 

Question 9: 

What are the limitations of the study?..........................................................37
 

Question 10:
 

What can wire and cable suppliers, manufacturers, and waste managers
 

do to reduce environmental impacts? ..........................................................40
 
         

     

       

   

IN T R O D U C T I O N

Purpose and Scoe of the Study

The purpose of the Wire and Cable Partnership was to evaluate the life­cycle

environmental impacts of standard (leaded) and alternative (lead­free and/or zerohalogen) cable insulation and jacketing formulations for three cable types (CMR, CMP,

and NM­B) using the life­cycle assessment (LCA) approach.  LCAs, which are generally

global and non­site specific in scope, look at the full life cycle of the product being

evaluated, from materials acquisition to manufacturing, use, and end­of­life (i.e., final

disposition).  The WCP LCA considers 14 impact categories, which are related to

material consumption, energy use, air resources, water resources, landfills, and

human and ecological toxicity.

Need for the Study

The wire and cable industry manufactures a wide range of products that support a

multitude of applications.  Many wire insulation and cable jacketing compositions

contain materials, such as lead, halogenated compounds, and other ingredients, that

impart electrical insulation and fire performance properties, but that have been

identified as materials of potential environmental concern or as materials for which

industry stakeholders have expressed a desire to identify and evaluate various

alternatives.  The DfE/TURI Partnership has generated information on the

environmental impacts of leaded (baseline) and alternative cable constructions in

order to help companies make environmentally sound product and material choices.

Although some changes have been made in certain wire and cable sectors, the WCP

believes that developing and providing sound environmental data using a life­cycle

assessment approach could assist those and other sectors to pursue environmentally

preferable cables.  Because of the large quantity of cable put into commerce every

year, choosing environmentally preferable materials could have a broad impact on

public health and the environment.  Quantitative environmental life­cycle analysis of

the baseline and alternative cable formulations is needed, given the current interest

in lead­free cables in the United States and halogen­free cable materials in certain

overseas markets, the potential environmental concerns that lead­ and halogencontaining additives pose, and the fact that the relative life­cycle environmental

impacts of these cable formulations have not yet been determined.  This project

offers the opportunity to mitigate current and future risks by assisting the wire and

cable industry in identifying cable jacketing and wire insulation formulations that are

less toxic and that pose fewer risks over their life cycles, and identifying areas for

environmental improvement.

About EPA’s Design for the 

Environment Program 

EPA’s Office of Pollution

Prevention and Toxics

established the DfE Program

in 1992 to encourage

businesses to incorporate

environmental concerns into

their business decisions.  DfE

industry projects are

cooperative, joint

partnerships with trade

associations, businesses,

public­interest groups, and

academia to assist

businesses in specific

industries to identify and

evaluate more

environmentally sound

products, processes,

technologies, and

formulations.  The DfE Wire

and Cable Partnership

consists of individual wire and

cable manufacturers, supply

chain members, trade

association members,

environmental researchers, a

state funded research and

assistance organization, and

EPA.

1
       

     

   

   

What is a life­cycle assessment? 

The DfE Wire and Cable Partnership (WCP) conducted this analysis of wire and cable

products using a life­cycle assessment (LCA) approach, which allows for a

comprehensive analysis of the environmental consequences of a product system over

its entire life.  LCA, which is increasingly being used by industry, contains four major

steps:

1.	 Goal Definition and Scoping lays out why the LCA is being conducted, its 

intended use, and the system or data categories to be studied.

2.	 Life­Cycle Inventory (LCI) involves quantifying inputs (e.g., raw materials and 

fuel) and outputs (e.g., emissions, effluents, and products).

3.	 Life­Cycle Impact Assessment (LCIA) involves characterizing the effects of the 

inputs and outputs (as identified in the life­cycle inventory step) on the 

environment and human and ecological health.

4.	 Life­Cycle Interpretation analyzes major contributions, conducts sensitivity 

analysis and uncertainty analyses as warranted, and presents conclusions. 

This study presents results, but does not make recommendations as to 

preferred products or specific material choices, which is left to the wire and 

cable industry and others to complete.  Using the results of this study; 

however, opportunities for improvement are introduced.

In the LCI and LCIA steps, the inputs and outputs, and environmental impacts

associated with the product throughout its life are quantified and characterized for

each life­cycle stage:  raw material extraction, materials processing, product

manufacturing, product use, and end­of­life.  Each of these major stages of the

product life cycle is described in Figure 1.1.

2
Figure 1.1   Life­Cycle Stages of Wire and Cable Evaluated in this Study    
 

3
         

     

Which wire and cable products were 

investigated during the project? 

This project investigated baseline and alternative cable formulations within three

different types of wire and cable products:  (1) Category 6 riser­rated communication

cable (CMR); (2) Category 6 plenum­rated communication cable (CMP); and (3) nonmetallic sheathed low­voltage power cable as used in building wire (NM­B).  These

products were chosen by the project partners because together they (1) contain

materials common to many wire and cable applications, (2) typically contain materials

for which alternatives are being sought, and (3) represent a significant share of the

wire and cable market.  In particular, this report focuses on lead­stabilized and leadfree cable constructions within each product type.  For CMR, a zero­halogen cable

also was examined, though the limited available data only allowed for a partial cradleto­gate assessment.

A typical cable product consists of a wire conductor (typically copper) covered by

insulation, and a jacket that encases the insulated wire(s).  The resins used for the

insulation of NM­B and for the jacketing of CMR, CMP, and NM­B cables are

compounded with other materials, such as heat stabilizers and flame retardants, in

order to meet performance specifications.

The goal of the WCP was to evaluate as many lead­free and halogen­free cables as

possible for each of the three cable types.  Project partners assisted in identifying the

baseline and alternative cable constructions for the three different cable products.

Table 2.1 lists the general characteristics and makeup of each cable type.

Functional Unit

In an LCA, product systems are evaluated on a functionally equivalent basis.  The

functional unit normalizes data based on equivalent use to provide a reference for

relating process inputs and outputs to the inventory and impact assessment across

cables.  The product systems evaluated in this project are baseline (i.e., leaded) and

alternative (i.e., lead­free and zero­halogen) cable wire insulation and cable jacketing

formulations, as used in telecommunication and low­voltage power cable installations

in the United States.  Each of the three cable types was evaluated in separate 4
analyses, as each type has a different functionality.  The functional unit for each cable

type is the insulation and jacketing used in a linear length of cable (one kilometer),

which would be used to transmit a signal that meets Underwriters Laboratories (UL)

performance requirements and fire safety specifications for each product type.

5
       

   

How were environmental and health 

impacts evaluated? 

The life­cycle environmental and health impacts of wires and cables were evaluated

through two sequential phases:  (1) life­cycle inventory and (2) life­cycle impact

assessment.

Life­Cycle Inventory (LCI)

The LCI tallies the material and energy inputs and the environmental releases

(collectively referred to as “flows”) throughout the products’ life cycles.  Given the

enormous amount of data involved in creating an inventory of all of the input and

output flows for a product system, decision rules were used to determine which cable

materials would be included as entire upstream processes.  The decision rule process

began by assessing the materials used in cable production for the following attributes:

!	 The mass contribution of each material. With a greater mass of materials

and resources consumed, the potential for a material to have a significant 

environmental impact increases.

! Materials that are of known or suspected environmental significance (e.g., 

toxic). To the extent feasible, the process considers materials or components 

known or suspected to exhibit an environmental hazard.

! Materials known or suspected to have a large contribution to the system’s 

energy requirements. Because many environmental impacts can be 

associated with energy consumption, priorities were given to including 

materials or processes that are known or suspected to consume large

amounts of energy.

! Materials which are physically or functionally unique to one cable formulation

over another. The physical or functional uniqueness of a material or 

component could be identified by chemical makeup or by size.

Attempts were made to include all materials greater than five percent by weight.

Materials between one percent and five percent by mass were subject to inclusion

based on other decision rules or data availability.  Materials of known or suspected

environmental or energy significance were also included, regardless of their mass

contribution.  Materials that are physically or functionally unique to a cable product

compared to the baseline (leaded) construction, as determined by the Core Group,

6
   

Figure 3.1.  Criteria for Selecting Inputs
 

are also considered if they would have been otherwise eliminated based on the mass

cutoff.  Figure 3.1 is a graphical representation of these decision rules.

In considering upstream materials, in addition to applying the decision rules, a

combination of other factors was also considered, including availability of existing

data and manufacturers’ willingness to participate.  When an inventory of a

production process for a material identified by the decision rules could not be

obtained, the material still remained in the inventory for the cable (what is not

included are all the flows associated with producing that material).

Based on the LCI data obtained for this study, 2 of the 4 analyses were based on the

full life cycle:  materials extraction (“upstream”), manufacturing, and end­of­life (EOL)

stages.  The remaining 2 analyses were based on only upstream and manufacturing

stages:

! Full life cycle

Leaded and lead­free CMR Category 6 insulation and jacketing

Leaded and lead­free CMP Category 6 insulation and jacketing

! Partial life cycle

Leaded and lead­free vs.  zero­halogen CMR Category 6 insulation and

jacketing.  

Leaded and lead­free NM­B power cable insulation and jacketing

The processes included in the full life­cycle analyses are presented in Figure 3.2.  The

processes in the partial life­cycle analyses are a subset of processes shown for the

full life cycles.

Life­Cycle Impact Assessment (LCIA) 7
Figure 3.2   Generic Process Flows for All Cables Evaluated in the WCP
 

The LCIA is the process by which the environmental burdens identified in the LCI are

translated into environmental impacts.  It is important to note that direct comparisons

cannot be made across impact categories, because impacts in different impact

categories are generally calculated based on different scales.  The WCP LCIA

consisted of two steps:  classification and characterization.

Classification – The process of assigning and aggregating data from inventory studies

to impact categories.  The WCP LCA places inventory data into one or more of 14

impact categories.  These categories cover a range of effects that address natural

resources impacts, abiotic ecosystem impacts, and human health and ecotoxicity.

Characterization – The characterization step of LCIA includes the conversion and

aggregation of LCI results to common units within an impact category.  Different

assessment tools are used to quantify the magnitude of potential impacts, depending

on the impact category.  Three types of approaches are used in the characterization

method for the WCP:

! Loading – An impact score is based on the inventory amount.

! Equivalency – An impact score is based on the inventory amount weighed by

a certain effect, equivalent to a reference chemical.

8 ! Scoring of inherent properties – An impact score is based on the inventory 
amount weighed by a score representing a certain effect for a specific

material (e.g., toxicity impacts are weighed using a toxicity scoring method).

Table 3.1 presents the 14 impact categories and a description of how each was

calculated.

9
             

   

       

  

       

         

How was uncertainty in the wire and cable
 

life cycle addressed? 

Uncertainty Analysis

Four parameters within the life­cycle processes of the CMP and CMR cables were

considered to be highly uncertain and were modeled as uniform distributions, using

Monte Carlo statistical methods.  These uncertainties only applied to the CMR and

CMP analyses where the full life cycle was evaluated and where there was a large

discrepancy in the extrusion energy data.  The first three parameters below are from

the EOL stage and the fourth is from the manufacturing stage.

! Cable consumed in fire – The parameter representing the percentage of 

cable consumed in fire was selected as highly uncertain due to the lack of 

information about building cable burned in fire.  The frequency of fires in 

buildings containing the cables of interest was well characterized, and the 

natural extreme bounds were that anywhere from 0% to 100% of the cable 

contained in these buildings would burn in the fire (equivalent to 0­1.1% of all 

cable installed).  However, we chose 10% of cables that burn in a structure fire 

as a central estimate because fire protection methods would skew actual burn 

percentages toward the lower end, and bounded the distribution at 0 and 

20%.

! Proportion of cable to recycling – The percentage of cable insulation and

jacketing resins going to recycling was another source of substantial 

uncertainty in the EOL stage.  Using an upper estimate based on data from 

Europe (20% of recovered wire and cable resins are recycled), a range of 0% 

to 20% of the cable resins was modeled as being recycled. 

! Proportion of lead leached from landfills – The parameter representing the

percentage of lead leached into the ground assumed that 0­100% of the 

leachate would ultimately escape any landfill lining and leachate collection 

system (equivalent to 0­1.5% of total lead escaping for cable directly 

landfilled, or equivalent to 0­10% of total lead escaping for cable resins 

landfilled after chopping—a process that is used to recover the copper 

conductor). 

10 ! Extrusion energy – Inconsistent and highly divergent inter­company energy
values led to high uncertainty in the cable extrusion energy data.  Thus, the 

range of the data sets collected as primary data for the lead­free cable were 

used to set the bounds of the uncertainty analysis, given that none of the data

could be identified as anomalous.  Because the baseline cable pulled

energy  use values from only one data set, a proxy data set that produced an 

equivalent uncertainty range in extrusion energy use was incorporated.  A 

uniform distribution was used to bound the energy used in the baseline and 

lead­free cable extrusion inventories.

Sensitivity Analysis

The uncertainty of impact category results was a result of the concurrent variation of

the four parameters.  Therefore, a sensitivity analysis was necessary to assess the

magnitude of each parameter’s contribution.  A built­in sensitivity analysis function

from the GaBi4 LCA software was used to determine the amount of variance in each

impact category attributable to each of the dynamic parameters.

11
         

         

           

          

What are the health and environmental 

impacts of baseline, lead­free, and zerohalogen CMR cables, and what drives the
 

impacts? 

This section presents the results for each impact category described in Question 3 for

CMR cable.  Although some LCAs assign importance ranks or weights to impact

categories, this LCA does not, because ranking impact categories requires subjective

choices that may not be appropriate for all stakeholders.  The major focus was on the

full life­cycle impacts of the baseline (lead­stabilized) cable and lead­free cable.  A

less comprehensive analysis was undertaken in the case of the partial life­cycle (or

cradle­to­gate) impacts among the baseline, lead­free, and zero­halogen cables.  Due

to a lack of data, only the upstream energy use and resin production were modeled

for the three cable types in the zero­halogen case.

Full Life Cycle: Baseline and Lead­Free

For each impact category, Table 5.1 presents life­cycle impact indicator scores for the

baseline cable and the lead­free cable, the percent difference between the two

cables, a data quality rating, and an indication of possible significance.  Highlights

from the results are as follows:

!	 The baseline cable had the greatest environmental burden (negative percent

change) in 8 impact categories, 2 of which may be statistically significant.

! The lead­free cable had the greatest environmental burden (positive percent 

change) in 6 impact categories, 2 of which may be statistically significant.

!	 All 4 potentially significant differences were for toxicity impact categories.

!	 The 2 largest absolute percent changes (potential public non­cancer and 

potential aquatic ecotoxicity) are statistically significant, and showed a greater 

environmental burden for the baseline cable.

Figures 5.1 and 5.2 show the relative differences between baseline and lead­free

12
cables within the 14 environmental and human health impact categories presented in

Table 5.1.  The values in Figures 5.1 and 5.2 are the log of the ratio of the baseline

cable impact score to that of the lead­free cable impact score.  Positive log ratios

indicate greater environmental burden for the baseline cable, and negative log ratios

indicate greater environmental burden for the lead­free cable.  Note that relative

differences should only be examined within and not across impact categories

because there is no association between relative differences in one category

compared to that of another.  Further, the relative differences depicted for each

impact category are not normalized to indicate any significance of the impacts

themselves; they only show the relative difference between the baseline and

alternative cables.

13
Figure 5.1  Relative CMR Impacts:  Baseline and Lead­free
 

NOTE:  Log ratio > 0 indicates greater environmental burden for baseline cable; 

do not compare across impact categories.

Figure 5.2  Relative CMR Impacts:  Baseline and Lead­free

(Public Non­cancer and Ecotoxicity)

NOTE:  Log ratio > 0 indicates greater environmental burden
 

for baseline cable; do not compare across impact categories.
 

14
Which          Processes Drive the Impact Scores?

A summary of the top contributing processes and material flows (i.e., input or output)

for baseline and lead­free cables by impact category is presented in Table 5.2.

! For the baseline cable, electricity generation is the top contributing process

for 6 of the 14 impact categories.

! For the lead­free cable, electricity generation is the top contributing process 

for 8 of the 14 impact categories.

15
   

   

     

   

   

   

Natural Resource Impacts

Non­renewable resource use/depletion: Non­renewable natural resources are

typically abiotic materials, such as mineral ore or fossil fuels.  For both the baseline

and lead­free cables, electricity generation contributes more than any other process

to the non­renewable resource use impact category.  Electricity generation contributes

74% of the total non­renewable resource use impact for the baseline cable and 71%

for the lead­free cable.  Inert rock is the top contributing material input flow for both

cables, representing 60% of the impact for the baseline cable and 57% for the leadfree cable.

Energy use: Energy use impact scores are the sum of electrical and fuel energy

inputs.  The generation of electricity drives the impact for both baseline and lead­free

cables, contributing 37% and 32% of the total energy use impact, respectively.

Natural gas is the top contributing material flow for both cables, representing 29% of

the impact for the baseline cable and 31% for the lead­free cable.

Landfill space use: Landfill space use impacts are calculated based on the volume of

landfill space consumed by solid, hazardous, and/or radioactive waste.  The

municipal solid waste landfilling process dominates landfill space use impacts,

contributing 76% of the total impact for both baseline and lead­free cables.  PVC

waste is the top contributing material flow for both cables, representing 46% of the

impact for each cable.

Abiotic Ecosystem Impacts

Global warming: The impact scores for the effects of global warming and climate

change are calculated using the mass of a global warming gas released to air,

modified by a global warming potential equivalency factor.  The generation of

electricity drives this impact category, contributing 56% of the total impact for the

baseline cable, and 50% for the lead­free cable.  Electricity generation produces

considerable amounts of carbon dioxide, a global warming gas.  Carbon dioxide is the

top contributing material flow for both cables, representing 85% of the impact for the

baseline cable and 83% for the lead­free cable.

Stratospheric ozone depletion:  Ozone depletion impact scores are based on the

identity and amount of ozone­depleting chemicals that are released to air.  Electricity

generation contributes 97% of the total impact for the baseline cable, and 95% for the

lead­free cable.  CFC­11 is the top contributing material flow for both cables,

representing 44% of the impact for the baseline cable and 43% for the lead­free

cable.

16
   

   

     

         

Photochemical smog: Photochemical smog refers to the release of chemicals that

may react with sunlight in the atmosphere to produce photochemical oxidants, such

as tropospheric ozone.  The production of jacketing resin is the top contributor to the

photochemical smog impact for both baseline and lead­free cables, contributing 45%

and 50%, respectively, to the total impact.  Unspecified volatile organic compounds

(VOCs) are the top contributing material flow for both cables, representing 70% of the

impact for the baseline cable and 74% for the lead­free cable.

Acidification: Acidification impacts refer to the release of chemicals that may

contribute to the formation of acid precipitation.  The generation of electricity drives

the acidification impact, contributing 56% and 49% of the total impact for baseline

and lead­free cables, respectively.  Sulfur dioxide is the top contributing material flow

for both cables, representing 63% of the impact for the baseline cable and 60% for

the lead­free cable.

Air particulates: Air particulate impacts are based on the amount of particulate

matter with an average aerodynamic diameter less than 10 micrometers (PM10) that

is released to the air.  Jacketing resin production drives the air particulates impact,

contributing 37% and 42% of the total impact for baseline and lead­free cables,

respectively.  Dust is the top contributing material flow for both cables, representing

99% of the impact for the baseline cable and 98% for the lead­free cable.

Water eutrophication (nutrient enrichment): Eutrophication (nutrient enrichment)

impacts to water are based on the identity and concentrations of eutrophication

chemicals released to surface water after treatment.  The generation of electricity

drives the total impact, contributing 91% and 89% of the total impact for baseline and

lead­free cables, respectively.  Chemical oxygen demand is the top contributing

material flow for both cables, representing 94% of the impact for the baseline cable

and 93% for the lead­free cable.

Human Health and Ecotoxicity

Occupational health – potential non­cancer toxicity:  Occupational impact scores are

based on the potential toxicity of material inputs to each process.  This

characterization method does not necessarily indicate where actual exposure is

occurring.  Instead, it uses the inputs of potentially toxic materials as surrogates for

exposure.  The materials used during jacketing compounding drive potential noncancer occupational health impacts, contributing 93% and 94% of the total impact for

baseline and lead­free cables, respectively.  A non­halogen flame retardant 17
           

         

         

   

(proprietary) is the top contributing material flow for both cables, representing 89% of

the impact for the baseline cable and 91% for the lead­free cable.

Occupational health – potential cancer toxicity: Materials used during jacketing

compounding drive potential cancer occupational health impacts, contributing 95%

and 84% to the total impact of baseline and lead­free cables, respectively.

Unspecified phthalates are the top contributing material flow for both cables,

representing 64% of the impact for the baseline cable and 62% for the lead­free

cable.  Unspecified phthalates, as a group, do not have specific toxicological data and

therefore are characterized by a default toxicity hazard value, which assumes the

toxicity is equivalent to the geometric mean of all chemicals used to determine the

relative toxicity. 

Public health – potential non­cancer toxicity: Impact scores are calculated based on

the identity and amount of toxic chemical outputs with dispositions to air, soil, and

water.  Inventory items do not truly represent long­term exposure.  Instead, impacts

are relative toxicity weightings of the inventory.  For the baseline cable, releases from

landfilling municipal solid wastes are the greatest single contributor to potential noncancer public health impacts, contributing 59% of the total impact.  For the lead­free

cable, emissions during electricity generation are the greatest single contributors to

potential non­cancer public health impacts, contributing 58% of the total impact.

Lead in water is the top contributing material flow for the baseline cable, representing

74% of the total impact.  Sulfur dioxide is the top contributing material flow for the

lead­free cable, representing 99% of the total impact.

Public health – potential cancer toxicity: Emissions from jacketing resin production

drive the impact score for both baseline and lead­free cables.  Jacketing resin

production contributes 37% of the total impact for baseline cable, and 44% for leadfree cable.  Nitrogen oxides (NOx) are the top contributing material flow for both

cables, representing 41% of the impact for the baseline cable and 40% for the leadfree cable.  NOx are characterized by a default toxicity hazard value. 

Potential aquatic ecotoxicity: Potential aquatic ecotoxicity impacts refer to the effects

of chemical outputs on non­human living organisms in freshwater aquatic

ecosystems.  Emissions from landfilling municipal solid wastes drive aquatic

ecotoxicity impacts for baseline cables, contributing 79% of the total impact.

Emissions from electricity generation drive potential aquatic ecotoxicity impacts for

lead­free cables, contributing 77% of the total impact.  Lead in water is the top 18
         

contributing material flow for the baseline cable, representing 99% of the total

impact.  Dissolved chlorine is the top contributing material flow for the lead­free

cable, representing 97% of the total impact.

Partial Life Cycle 3­Way Analysis: Baseline, Lead­Free, and Zero­Halogen

The 3­way CMR analysis (baseline versus lead­free versus zero­halogen)

demonstrated that within the cradle­to­gate analysis, the zero­halogen cable used far

more energy than the baseline or lead­free cable.  This was a function of more energy

required per mass of compounded resin produced, as well as the zero­halogen cable

having a higher mass to length ratio.  Thus, on a functional unit basis, the total energy

requirement was much larger (quantities withheld for proprietary considerations).  In

the CMR 3­way results, the production of electricity drove most impact categories,

except for landfill space use and potential occupational non­cancer and cancer

toxicity, for which the jacketing process was the top contributor.  For air particulate

production, the lead and lead­free cables were driven by jacketing compounding, but

the zero­halogen was driven by electricity production.  Note that the robustness of

these data is limited, as the zero­halogen data are only based on one company’s

data.  Further, this analysis does not provide full life­cycle information and should not

be construed to represent full life­cycle impacts.

These results also demonstrate that limiting the focus to a few manufacturing

processes, even on a functionally equivalent basis, does not adequately estimate

impacts over the full life cycle.  This is evidenced by comparing the full CMR life­cycle

analysis with the partial life­cycle analysis, which only takes into consideration

jacketing compounding and associated energy.  In the full life­cycle analysis, the leadfree cable had lower impact indicators than the baseline in 8 impact categories;

however, for the partial analysis, only 1 category had lower impact indicators for the

lead­free cable.  Of the 5 categories in the full life­cycle analysis that had the greatest

likelihood of statistically significant differences, 3 had results reversed in the partial

life cycle (i.e., significantly less burden in the full life cycle versus more burden in the

partial life cycle or vice versa):  potential occupational cancer toxicity, potential public

non­cancer toxicity, and potential aquatic ecotoxicity. 

19
         

         

         

What are the health and environmental 

impacts of baseline and lead­free CMP 

cables, and what drives the impacts? 

This section presents the results for each impact category described in Question 3 for

CMP cable.  Although some LCAs assign importance ranks or weights to impact

categories, this LCA does not, because ranking impact categories requires subjective

choices that might not be appropriate for all stakeholders.

For each impact category, Table 6.1 presents life­cycle impact indicator scores for the

baseline and lead­free cables, the percent difference between the two cables, a data

quality rating, and an indication of possible significance.  Highlights from the results

are as follows:

! The baseline cable had a greater environmental burden (negative percent 

change) for 12 impact categories, 4 of which may be statistically significant.

20
! The lead­free cable had a greater environmental burden (positive percent 

change) for 2 impact category, one of which is statistically significant.

! Of the 5 impact categories with potential statistical significance, 4 were 

related to toxicity.

! The 2 largest absolute percent changes (potential public non­cancer and

potential aquatic ecotoxicity) were statistically significant, and show a greater 

environmental burden for the baseline cable.

Figures 6.1 and 6.2 show the relative differences between baseline and lead­free

cables within the 14 environmental and human health impact categories presented in

Table 6.1.  The values in Figures 6.1 and 6.2 are the log of the ratio of the baseline

cable impact score to that of the lead­free cable impact score.  Positive log ratios

indicate greater environmental burden for the baseline cable, and negative log ratios

indicate greater environmental burden for the lead­free cable.  Note that relative

differences should only be examined within and not across impact categories,

because there is no association between relative differences in one category

compared to that of another.  Further, the relative differences depicted for each

impact category are not normalized to indicate any significance of the impacts

themselves; they only show the relative difference between the baseline and

alternative cables.

Figure 6.1  Relative CMP Impacts:  Baseline and Lead­free

NOTE:  Log ratio > 0 indicates greater environmental burden for baseline cable;

do not compare across impact categories. 21
         

   

   

   

Figure 6.2  Relative CMP Impacts:  Baseline and Lead­free
 

(Public Non­cancer and Ecotoxicity)
 

Which Processes Drive the Impact Scores?

A summary of the top contributing processes and material flows for baseline and

lead­free cables by impact category is presented in Table 6.2.

! For the baseline cable, both insulation and jacketing resin production are the

top contributing process for 3 of the 14 impact categories.

! For the lead­free cable, electricity generation is the top contributing processes 

for 5 of the 14 impact categories.

Natural Resource Impacts

Non­renewable resource use/depletion: Non­renewable natural resources are

typically abiotic materials, such as mineral ore or fossil fuels.  Electricity generation

drives non­renewable resource use impacts, contributing 65% and 64% of the total

impact for baseline and lead­free cables, respectively.  Inert rock is the top

contributing material flow for both cables, representing 52% of the total impact for

each cable.

Energy use: Energy use impact scores are the sum of electrical and fuel energy

inputs.  Electricity generation drives energy use impacts, contributing 29% and 28% of

the total impact for baseline and lead­free cables, respectively.  Natural gas is the top

contributing material flow for both cables, representing 60% of the total impact for

each cable.

22
     

   

Landfill space use: Landfill space use impacts are calculated based on the volume of

landfill space consumed by solid, hazardous, and/or radioactive waste.  The

municipal solid waste landfilling process drives landfill space use impacts,

contributing 66% and 69% of the total impact for baseline and lead­free cables,

respectively.  PVC waste is the top contributing material flow for both cables,

representing 40% of the impact for the baseline cable and 42% for the lead­free

cable.

Abiotic Ecosystem Impacts

Global warming: The impact scores for the effects of global warming and climate

change are calculated using the mass of a global warming gas released to air,

modified by a global warming potential equivalency factor.  For the baseline cable,

electricity generation drives global warming impacts, contributing 74% of the total

impact.  For the lead­free cable, insulation resin production drives global warming

impacts, contributing 68% of the total impact.  Carbon dioxide is the top contributing

material flow for both cables, representing 48% of the impact for the baseline cable

and 47% for the lead­free cable. 23
   

   

Stratospheric ozone depletion: Ozone depletion impact scores are based on the

identity and amount of ozone depleting chemicals that are released to air.  Insulation

resin production drives stratospheric ozone depletion impacts, contributing 88% and

87% of the total impact for baseline and lead­free cables, respectively.  Refrigerant #5

is the top contributing material flow for both cables, representing 84% of the total

impact for each cable.

Photochemical smog:  Photochemical smog refers to the release of chemicals that

may react with sunlight in the atmosphere to produce photochemical oxidants, such

as tropospheric ozone.  Jacketing resin production drives photochemical smog

impacts, contributing 44% and 47% of the total impact for baseline and lead­free

cables, respectively.  Unspecified volatile organic compounds (VOCs) are the top

contributing material flow for both cables, representing 43% of the impact for the

baseline cable and 45% for the lead­free cable.

Acidification: Acidification impacts refer to the release of chemicals that may

contribute to the formation of acid precipitation.  Electricity generation drives

acidification impacts, contributing 68% and 66% of the total impact for baseline and

lead­free cables, respectively.  Sulfur dioxide is the top contributing material flow for

both cables, representing 65% of the impact for the baseline cable and 64% for the

lead­free cable.

Air particulates: Air particulate impacts are based on the amount of particulate

matter with an average aerodynamic diameter less than 10 micrometers (PM10) that

is released to the air.  Electricity generation drives air particulate impacts,

contributing 47% and 44% of the total impact for baseline and lead­free cables,

respectively.  Dust is the top contributing material flow for both cables, representing

95% of the total impact for each cable.

Water eutrophication (nutrient enrichment): Eutrophication (nutrient enrichment)

impacts to water are based on the identity and concentrations of eutrophication

chemicals released to surface water after treatment.  Electricity generation drives

eutrophication impacts, contributing 96% of the total impact for both baseline and

lead­free cables.  Chemical oxygen demand is the top contributing material flow for

both cables, representing 95% of the impact for the baseline cable and 94% for the

lead­free cable.

24
     

         

       

         

         

     

Human Health and Ecotoxicity

Occupational health – potential non­cancer: Occupational impact scores are based

on the potential toxicity of material inputs to each process.  This characterization

method does not necessarily indicate where actual exposure is occurring.  Instead, it

uses the inputs of potentially toxic materials as surrogates for exposure.  Materials

used during natural gas production drive potential non­cancer occupational health

impacts, contributing 46% of the total impact for both baseline and lead­free cables.

Natural gas is the top contributing material flow for both cables, representing 48%

and 45% of the total impact for baseline and lead­free cables, respectively.  Natural

gas is characterized by a default toxicity hazard value.

Occupational health – potential cancer: Materials used during cable jacketing

compounding drive potential cancer occupational health impacts, contributing 86%

and 84% of the total impact for baseline and lead­free cables, respectively.  Flame

retardant #3, a proprietary material, is the top contributing material flow for both

cables, representing 28% of the impact for the baseline cable and 29% for the leadfree cable.  Flame retardant #3 is characterized by a default toxicity hazard value. 

Public health – potential non­cancer: Impact scores are calculated based on the

identity and amount of toxic chemical outputs with dispositions to air, soil, and water.

Inventory items do not truly represent long­term exposure.  Instead, impacts are

relative toxicity weightings of the inventory.  For the baseline cable, emissions from

landfilling municipal solid waste drive potential non­cancer public health impacts,

contributing 44% of the total impact.  For lead­free cables, electricity generation

drives potential non­cancer public health impacts, contributing 73% of the total

impact.  Lead in water is the top contributing material flow for the baseline cable,

representing 56% of the total impact.  Sulfur dioxide in air is the top contributing

material flow for the lead­free cable, representing 98% of the total impact.

Public health – potential cancer: Electricity generation drives potential cancer public

health impacts, contributing 44% and 42% of the total impact for baseline and leadfree cables, respectively.  Nitrogen oxides (NOx) are the top contributing material flow

for both cables, representing 44% of the total impact for each cable.  Nitrogen oxides

are characterized by a default toxicity hazard value.

Potential aquatic ecotoxicity: Potential aquatic ecotoxicity impacts refer to the effects

of chemical outputs on non­human living organisms.  For the baseline cable,

emissions from landfilling municipal solid waste drives potential aquatic ecotoxicity 25
impacts, contributing 78% of the total impact.  For the lead­free cable, emissions from

electricity generation drive potential aquatic ecotoxicity impacts, contributing 94% of

the total impact.  Lead in water is the top contributing material flow for the baseline

cable, representing 98% of the total impact.  Dissolved chlorine is the top contributing

material flow for the lead­free cable, representing 81% of the total impact. 

26
         

         

         

What are the health and environmental 

impacts of baseline and lead­free NM­B 

cables, and what drives the impacts? 

This section presents the results for each impact category described in Question 3 for

NM­B cable.  The cradle­to­gate analysis examined only part of the cable life cycle,

from material extraction to the compounding of the cable insulation and jacketing.

Cable manufacturing (extrusion) was excluded as project researchers were unable to

obtain a complete data set for this process.  Subsequently, EOL could not be

adequately modeled, because the output from cable manufacturing (extrusion) to EOL

was not known.  Although some LCAs assign importance ranks or weights to impact

categories, this LCA does not, because ranking impact categories requires subjective

choices that may not be appropriate for all stakeholders.

For each impact category, Table 7.1 presents life­cycle impact indicator scores for the

baseline and lead­free cables, the percent difference between the two cables, and a

data quality rating.  Highlights from the results are as follows:

! The baseline cable has a greater environmental burden for 13 impact 

categories (negative percent change).

! The lead­free cable has a greater environmental burden for 1 impact category 

(positive percent change).

27
         

Figure 7.1 displays the relative differences between baseline and lead­free cables

within the 14 environmental and human health impact categories presented in Table

7.1.  The values in Figure 7.1 are the log of the ratio of the baseline cable impact

score to that of the lead­free cable impact score.  Positive log ratios indicate greater

environmental burden for the baseline cable, and negative log ratios indicate greater

environmental burden for the lead­free cable.  Note that relative differences should

only be examined within and not across impact categories, because there is no

association between relative differences in one category compared to that of another.

Further, the relative differences depicted for each impact category are not normalized

to indicate any significance of the impacts themselves; they only show the relative

difference between the baseline and alternative cables.

Figure 7.1  Relative NM­B Impacts:  Baseline and Lead­free (partial life cycle)

NOTE:  Log ratio > 0 indicates greater environmental burden for baseline cable; 

do not compare across impact categories.

Which Processes Drive the Impact Scores?

A summary of the top contributing processes and material flows (i.e., input or output)

for baseline and lead­free cables by impact category is presented in Table 7.2.

! For the baseline cable, jacketing resin production is the most frequent top

contributor to impact categories (8 of 14 categories).

! the lead­free cable, jacketing resin production is the most frequent top 

contributor to impact categories (8 of 14 categories).

28
   

   

Natural Resource Impacts

Non­renewable resource use/depletion: Non­renewable natural resources are

typically abiotic materials, such as mineral ore or fossil fuels.  Jacketing resin

production drives non­renewable resource use and depletion, contributing 39% and

47% of the total impact for baseline and lead­free cables, respectively.  Inert rock is

the top contributing material flow for the baseline cable, representing 22% of the total

impact.  Natural gas is the top contributing material flow for the lead­free cable, also

representing 22% of the total impact. 

Energy use: Energy use impact scores are the sum of electrical and fuel energy

inputs.  Jacketing resin production drives energy use impacts, contributing 56% and

60% of the total impact for baseline and lead­free cables, respectively.  Natural gas is

the top contributing material flow for both cables, representing 42% of the impact for

the baseline cable and 43% of the impact for the lead­free cable. 

29
   

   

   

Landfill space use: Landfill space use impacts are calculated based on the volume of

landfill space consumed by solid, hazardous, and/or radioactive waste.  Limestone

production drives landfill space use impacts, contributing 64% of the total impact for

both baseline and lead­free cables.  Treatment residue is the top contributing

material flow for both cables, representing 66% of the impact for the baseline cable

and 64% of the impact for the lead­free cable. 

Abiotic Ecosystem Impacts

Global warming: The impact scores for the effects of global warming and climate

change are calculated using the mass of a global warming gas released to air,

modified by a global warming potential equivalency factor.  Jacketing resin production

drives global warming impacts, contributing 57% and 62% of the total impact for

baseline and lead­free cables, respectively.  Carbon dioxide is the top contributing

material flow for both cables, representing 89% of the total impact for each cable. 

Stratospheric ozone depletion: Ozone depletion impact scores are based on the

identity and amount of ozone depleting chemicals that are released to air.  Electricity

generation drives stratospheric ozone depletion impacts, contributing 77% and 81%

of the total impact for baseline and lead­free cables, respectively.  CFC­11 is the top

contributing material flow for both cables, representing 44% of the impact for the

baseline cable and 45% of the impact for the lead­free cable. 

Photochemical smog: Photochemical smog refers to the release of chemicals that

may react with sunlight in the atmosphere to produce photochemical oxidants, such

as tropospheric ozone.  Jacketing resin production drives photochemical smog

impacts, contributing 91% and 93% of the total impacts for baseline and lead­free

cables, respectively.  Unspecified volatile organic compounds (VOCs) are the top

contributing material flow for both cables, representing 77% of the impact for the

baseline cable and 79% of the impact for the lead­free cable. 

Acidification: Acidification impacts refer to the release of chemicals that may

contribute to the formation of acid precipitation.  Jacketing resin production drives

acidification impacts, contributing 71% and 77% of the total impacts for baseline and

lead­free cables, respectively.  Sulfur dioxide is the top contributing material flow for

both cables, representing 58% of the impact for the baseline cable and 56% of the

impact for the lead­free cable. 

30
  

   

     

         

         

         

Air particulates: Air particulate impacts are based on the amount of particulate

matter with an average aerodynamic diameter less than 10 micrometers (PM10) that

is released to the air.  Jacketing resin production drives air particulate impacts,

contributing 65% and 75% of the total impacts for baseline and lead­free cables,

respectively.  Dust is the top contributing material flow for both cables, representing

93% of the impact for the baseline cable and >99% of the impact for the lead­free

cable. 

Water eutrophication (nutrient enrichment): Eutrophication (nutrient enrichment)

impacts to water are based on the identity and concentrations of eutrophication

chemicals released to surface water after treatment.  Electricity generation drives

water eutrophication impacts, contributing 64% and 57% of the total impacts for

baseline and lead­free cables, respectively.  Chemical oxygen demand is the top

contributing material flow for both cables, representing 88% of the impact for the

baseline cable and 86% of the impact for the lead­free cable. 

Human Health and Ecotoxicity

Occupational health – potential non­cancer: Occupational impact scores are based

on the potential toxicity of material inputs to each process.  This characterization

method does not necessarily indicate where actual exposure is occurring.  Instead, it

uses the inputs of potentially toxic materials as surrogates for exposure.  Insulation

compounding drives potential non­cancer occupational health impacts, contributing

64% and 54% of the total impacts for baseline and lead­free cables, respectively.

Flame retardant #2 is the top contributing material flow for both cables, representing

58% of the impact for the baseline cable and 54% of the impact for the lead­ free

cable. 

Occupational health – potential cancer: Jacketing compounding drives potential

cancer occupational health impacts, contributing 85% and 94% of the total impacts

for baseline and lead­free cables, respectively.  Phthalate plasticizer #2 is the top

contributing material flow for the baseline cable, representing 81% of the total

impact.  Phthalate plasticizer #5 is the top contributing material flow for the lead­free

cable, representing 92% of the total impact.  Both phthalate plasticizers are

characterized by default toxicity hazard values.

Public health – potential non­cancer: Impact scores are calculated based on the

identity and amount of toxic chemical outputs with dispositions to air, soil, and water.

Inventory items do not truly represent long­term exposure.  Instead, impacts are 31
         

   

relative toxicity weightings of the inventory.  Jacketing resin production drives

potential non­cancer public health impacts, contributing 67% and 75% of the total

impacts, respectively, for baseline and lead­free cables.  Sulfur dioxide is the top

contributing material flow for both cables, representing 98% of the impact for the

baseline cable and 99% of the impact for the lead­free cable. 

Public health – potential cancer: Jacketing resin production drives potential cancer

public health impacts, contributing 64% and 57% of the total impacts, respectively, for

baseline and lead­free cables.  Nitrogen oxides (NOx) are the top contributing material

flows for the baseline cable, representing 34% of the total impact.  Unspecified

volatile organic compounds (VOCs) are the top contributing material flows for the leadfree cable, representing 35% of the total impact.  Both NOx and unspecified VOCs are

characterized by default toxicity hazard values. 

Potential aquatic ecotoxicity: Potential aquatic ecotoxicity impacts refer to the effects

of chemical outputs on non­human living organisms.  Plasticizer production drives

potential aquatic ecotoxicity impacts, contributing 51% and 81% of the total impacts,

respectively, for baseline and lead­free cables.  Copper +1 and +2 ions are the top

contributing material flow for both cables, representing 46% of the impact for the

baseline cable and 62% of the impact for the lead­free cable. 

32
         

   

Overall, where are the greatest potential
 

health and environmental impacts? 

CMR

The point estimate results from the CMR impact assessment showed mixed results

for both baseline and lead­free cable types, though the disparities between the cable

impact scores for most impact categories were minimal (Table 5.1).  In eight impact

categories, the lead­free cable construction had less environmental burden; however,

six of those categories generated inconclusive results due to the large impact

uncertainty.  In other words, overlap of the 10th and 90th percentiles eliminated the

possibility of statistically significant differences.  Two categories—potential public

chronic non­cancer toxicity and potential aquatic ecotoxicity—had less environmental

burden for the lead­free cable and did not have overlapping uncertainty ranges.  Of

the six categories that showed lower burdens for the baseline cable, only two did not

have overlapping results due to uncertainty:  potential occupational cancer and noncancer toxicity.  The following processes were the top contributors to a majority of the

impact categories for the CMR cables evaluated in this study (see Table 8.1): 

! Electricity Generation – Electricity generation was the top contributing

process in the baseline cable life cycle for 6 impact categories:  nonrenewable resource use, energy use, global warming, ozone depletion, air 

acidification, and eutrophication.  For the lead­free cable, the generation of 

electricity for cable extrusion was the top contributing process for the same 6 

impact categories, in addition to being the top contributor to the potential 

public non­cancer toxicity and potential aquatic toxicity impact categories. 

! Resin Production and Compounding – For both cables, jacketing resin 

production was the top contributing process for the photochemical smog 

formation, air particulates, and potential public cancer toxicity impact 

categories.  The compounding of the jacketing was the top contributing 

process to the potential occupational non­cancer and cancer toxicity impact 

categories for both cables]

! Landfilling – Municipal solid waste landfilling was the top contributing 

process to the potential public non­cancer toxicity and potential aquatic

ecotoxicity impact categories in the baseline case.  Lead from landfilling was  33
the top flow contributing to the potential public non­cancer toxicity and 

potential aquatic ecotoxicity impact categories.  Landfilling was not a top 

contributor to any of the impact categories for the lead­free cable.

These results help to identify potential areas of environmental improvement.

However, it must be noted that the results of this study are in the context of examining

the relative differences of resin systems and their additives.  Therefore, focusing

solely on the top contributors identified here does not provide complete life­cycle

impacts from the entire cable (e.g., impacts associated with the copper conductor

were not examined in this study).

The point­estimate results from the cradle­to­gate analyses of the baseline, lead­free,

and zero­halogen CMR cables showed that the zero­halogen cable had far greater

environmental burden in all of the impact categories, except for potential

occupational non­cancer toxicity.  These results were not presented with the same

level of detail as the other results, because the available upstream data for the

halogen­free cable only allowed for the modeling of the upstream energy production

and jacketing compounding processes.  Since the cable manufacturing (extrusion)

process was not included, this also precluded having data for downstream EOL

processes.

CMP

The point estimates from the CMP cable analyses showed that all impact categories,

except for potential occupational cancer toxicity and landfill space use, had fewer

impacts (i.e., less environmental burden) for the lead­free cable than for the baseline

cables.  However, only four of these impact categories — potential occupational noncancer toxicity, potential public chronic non­cancer toxicity, potential aquatic

ecotoxicity, and ozone depletion — did not have overlapping 10th and 90th

uncertainty ranges, suggesting greater confidence in these results.  The following

processes were the top contributors to a majority of the impact categories evaluated

in this study (see Table 8.1):

! Resin Production – The production of jacketing (PVC) and insulation (FEP)

resins were top contributors to 3 impact categories each.  For both baseline 

and lead­free cables, the production of the jacketing resin, PVC, was the top 

contributing process for the photochemical smog formation, air particulates, 

and potential public cancer toxicity impact categories, for which unspecified 

VOCs were the top contributing flow.  The production of FEP was the top 

34 contributing process to energy use, global warming, and ozone depletion.
! Electricity    Generation – The generation of electricity for cable extrusion was 

another major contributing process to both cables.  In the case of the baseline

cable, electricity generation was the top contributing process for the nonrenewable resources, air acidification, and eutrophication impact categories. 

In the case of the lead­free cable, electricity generation was the top 

contributor to the same impact categories, as well as to the potential public 

non­cancer toxicity and potential aquatic ecotoxicity impact categories. 

! Landfilling – For the baseline CMP cable, the top contributing process to the 

potential public non­cancer toxicity and potential aquatic ecotoxicity impact 

categories was municipal solid waste landfilling.  For both of these categories, 

the top contributor was lead, which was assumed to leach from the landfill 

into groundwater.  For both cables, the landfill space use impact category was 

also dominated by the municipal solid waste landfilling process. 

These results help to identify potential areas of environmental improvement.

However, it must be noted that the results of this study are in the context of examining

the relative differences of resin systems and their additives.  Therefore, focusing

solely on the top contributors identified here does not provide complete life­cycle

impacts for the entire cable (e.g., impacts associated with the copper conductor were

not examined in thisstudy).

NM­B

The point estimates from the NM­B cradle­to­gate cable comparisons showed that all

categories, except for potential occupational non­cancer toxicity, had fewer impacts

for the lead­free cables than for the baseline cables.  No uncertainty or sensitivity

analyses were run for this comparison because both cable extrusion and the end­oflife stages were excluded from the analyses due to lack of data, and those stages

were the only ones in which there were large uncertainties.

In the NM­B analysis, which excludes the extrusion process and subsequent

downstream processes, the production of the jacketing resin, PVC, is the top

contributor to eight impact categories.  It is followed by electricity generation from

compounding (2 categories), then limestone production (1 category), insulation

compounding (1 category), jacketing compounding (1 category), and phthalate

production (1 category) (see Table 8­1).  These results identify processes that could

be the focus of environmental improvement opportunities for upstream and cable 35
insulation compounding processes.  However, it must be noted that these results are

in the context of examining the relative differences of resin systems and their

additives.  Focusing solely on the top contributors identified here does not provide

complete life­cycle impacts for the entire cable (e.g., impacts associated with the

copper conductor were not examined in this study).  

36
           

     

What are the limitations of the study? 

LCA Limitations and Data Uncertainties

LCI

Uncertainty in the inventory data depends on how the data are characterized by

submitters, and other limitations identified during inventory data collection.  These

uncertainties are carried into the impact assessment.  Uncertainties in the inventory

data include, but are not limited to, the following:

! missing individual inventory items;

! missing processes or sets of data;

! estimation uncertainty;

! allocation uncertainty/working with aggregated data; and

! unspeciated chemical data.

In general, the number of primary data sets available for the upstream and

manufacturing processes was quite limited.  The greatest number of data sets

collected for a particular process was three (e.g., CMR jacketing compounding).

Where primary data could not be obtained, secondary data were used for some of the

upstream processes.  Further investigation into the proportion of the market modeled

in this LCA is necessary in order to understand the potential magnitude of the

uncertainty in the material and energy inputs derived from primary and secondary

data used in this study.

Additionally, the full life cycle was not included in the NM­B analysis due to lack of

available data.  Lacking the full life­cycle inventory for the NM­B cable type, it is

difficult to predict how the partial life­cycle impacts would compare to a full life cycle.

The partial life­cycle results can, however, inform decisions about material and energy

use during the cable insulation and jacketing compounding processes.

Sensitivity Analysis

The sensitivity analysis was used to probe the contributions to overall impact

uncertainty from each of the stochastic parameters (see Question 4).  Results of the

analysis, shown in Table 9.1, give the largest contributing parameter along with the

percent variance in the impact result attributable to this dominant parameter.  It is

evident that one parameter—the energy used for cable extrusion—is responsible for 37
         

       

most of the variation in impacts for each cable type.  However, for the CMR and CMP

baseline cables, the uncertainty in the potential public chronic non­cancer toxicity and

the potential aquatic ecotoxicity categories are dominated by the landfill leachate

parameter.  For all cables, thermoplastic recycling dominates the landfill space use

indicators.  The sensitivity analysis results showed that most categories were not

greatly affected by the EOL assumptions, especially the proportion of cable destroyed

in building fires.

LCIA

Some of the limitations and uncertainties in the LCIA derive from limitations and

uncertainties in the inventory stage; however, many are unique to the LCIA.  The 

limitations and uncertainties associated with the LCIA include but are not limited to

! Lack of Spatial and Temporal Relationships – The purpose of an LCIA is to 

evaluate the relative potential impacts of a product system for various impact 

categories.  There is no intent to measure the actual impacts or to provide 

spatial or temporal relationships linking the inventory to specific impacts.  The 

LCIA is intended to provide a screening­level evaluation of impacts. 

! Impact Score Parameter Uncertainty – Uncertainties are inherent in the 

parameters used to calculate the various impact scores.  For example, toxicity  38
   

     

         

data require extrapolations from animals to humans and from high to low 

doses (for chronic effects), resulting in a high degree of uncertainty.  Sources 

for each type of data should be consulted for more information on 

uncertainties specific to each parameter. 

! Chemical Ranking/Scoring System Uncertainty – Uncertainties exist in 

chemical ranking and scoring systems, such as the scoring of inherent 

properties approach used for human health and ecotoxicity effects.  In 

particular, systems that do not consider the fate and transport of chemicals in 

the environment can contribute to misclassifications of chemicals with 

respect to risk. 

!	 Chronic Toxicity Endpoint Uncertainty – Uncertainty is introduced where it was

assumed that all chronic endpoints are equivalent, which is likely not the 

case. 

! Screening Level Tool for Chemical Risk – The human health and ecotoxicity 

impact characterization methods presented in the WCP LCIA are screening 

tools that cannot substitute for more detailed risk characterization methods; 

however, the methodology is an attempt to consider chemical toxicity at a 

screening level for identifying potentially toxic materials in the inventory. 

Due to the limitations in the LCI data, no category was given a “high” relative quality

rating (see Tables 5.1, 6.1, and 7.1).  In addition to LCI uncertainty, LCIA uncertainty

contributes to the overall limitations.  The categories with greater model and data

uncertainty in the LCIA were given “medium” to “low” ratings.  For example, the

potential cancer impact category results were mostly based on materials that lack

data on carcinogenicity rather than being based on known carcinogens.  Also, as

specific gaps in data contributing to stratospheric ozone depletion were identified,

this category was given a “low” rating.  This was due to the lack of information on the

generation and emission of brominated organic byproducts during brominated

phthalate production.  Finally, the toxicity­based impact categories use inputs or

outputs as surrogates for exposure and do not model fate and transport and actual

exposure.  This could be the subject of further analysis, such as a targeted risk

assessment. 

39
         

         

   

What can wire and cable suppliers, 

manufacturers, and waste managers do to
 

reduce environmental impacts? 

This section identifies selected opportunities for reducing the overall environmental

and human health impacts of jacketing and insulation of communication cable

products, based on the results of the full life­cycle LCA results (CMR and CMP lead

and lead­free analyses).  Opportunities for improvement are broken down into three

categories:  upstream material production and use, electricity generation, and end­oflife disposition.

Upstream Materials

The upstream production and use of certain materials in wire and cable formulations

has a significant effect on many of the overall life­cycle impact category results.  The

materials that contribute to cable­associated environmental burden are, in order of

decreasing impact, lead heat stabilizers, jacketing and insulation resins, phthalate

plasticizers, and filler materials (e.g., calcined clay and limestone). 

Lead Heat Stabilizers

Lead byproducts that originate in the baseline cable heat­stabilizers are responsible

for much of the potential public non­cancer toxicity and potential aquatic ecotoxicity

burdens for both CMR and CMP baseline cables.  This is the most substantive

difference between the baseline and lead­free cables with regards to any of the

impact categories.  While there was confidence in the observed difference between

the leaded and lead­free cables, the absolute scores of each are dependent on

parameters that have not been well studied, such as the proportion of lead that

leaches out of landfilled resins and landfill failure rates.  Attempting to understand

the potential hazards inherent in the use of lead stabilizers is important for

stakeholders; however, this study cannot provide definitive findings about actual risk

or relative risk between baseline and alternative cables.  Because the environmental

impacts resulting from the use of lead heat stabilizers are seen primarily at the

product EOL, they are discussed further in the EOL disposition section below.

40
Jacketing      and Insulation Resins

The manufacture of jacketing and insulation resins contributes substantially to a

number of impact categories in both CMR and CMP cables, including energy use and

non­renewable resources, potential public cancer toxicity (NOx and VOC production),

potential occupational non­cancer toxicity (potentially toxic chemicals used in

jacketing/insulation resin production), air acidification, air particulate production, and

photochemical smog production.  Increasing the energy­efficiency of resin production,

and reducing or capturing air emissions is likely to reduce the overall environmental

burden.  The use of alternative input materials during jacketing and insulation resin

production might reduce overall environmental burden.  However, in order to

determine if this is the case, the life cycle analysis would have to be rerun,

substituting the new, less toxic materials.  

Phthalates

Phthalate plasticizers were major contributors to the potential occupational cancer

toxicity impacts, especially in the case of CMR cable, where they represented a far

higher fraction of the overall cable mass than in CMP cable.  Due to phthalates’

affinity for lipids, exposure in workers could potentially result in bioaccumulation over

time.  Though the issue of whether certain phthalates function as carcinogens has

not been entirely resolved, the monitoring of worker cohorts for phthalate body

burden and the minimization of direct contact with this suite of chemicals may be

advantageous.

Elecricity Generation

Electricity generation throughout the wire and cable life cycle, particularly for use in

upstream material production and cable extrusion, played an enormous role in the

overall environmental burden of wire and cable products analyzed here.  For the CMR

cables, the generation of electricity for cable extrusion was the top contributing

process in 6 and 8 impact categories for the baseline and lead­free cables,

respectively.  For the CMP cables, the generation of electricity for cable extrusion was

the top contributing process in 3 and 5 impact categories for the baseline and leadfree cables, respectively.  

Additionally, the sensitivity analysis (Table 9.1) revealed that the large impact

uncertainty ranges for both the CMR and CMP cables were mostly attributable to the

uncertainty in the energy needed for cable extrusion.  This was the case for all

categories except potential public non­cancer toxicity and potential aquatic

ecotoxicity, which were dominated by leachate uncertainty in the baseline cable, and 41
landfill space use, where the percentage of resins recycled after chopping had a

greater effect on the results for both cable types.  The range of extrusion energy,

modeled using a uniform uncertainty distribution, was quite large (>50% of the

aggregated value in both directions), so the resulting sensitivity of the model results

to this parameter was not entirely surprising.  However, the fact that the uncertainty

associated with the use of energy during cable extrusion is based on actual intercompany variability is a reminder that the sample size of the primary/secondary

datasets used, and the product or material market share represented by these

datasets, is important in determining the accuracy of the life­cycle modeling effort.

These findings suggest that identifying opportunities for reducing energy inputs would

likely have a large effect on many of the environmental and human health impact

scores for wire and cable products.

EOL Disposition

This study found that the end­of­life stage generates the most sizeable impact

differences between baseline leaded cable and lead­free cable.  For both CMR and

CMP, the difference between the two cables was most pronounced in the potential

public chronic non­cancer (CMR:  1,460 versus 279 kg noncancertox­equivalent;

CMP:  952 versus 358 kg noncancertox­equivalent) and potential aquatic ecotoxicity

impacts (CMR:  17.5 versus 0.113 kg aqtox­equivalent; CMP:  8.64 versus 0.151 kg

aqtox­equivalent), with the lead­free cables displaying much lower impacts in these

categories.  The sensitivity analysis demonstrated that the lead leachability

assumptions are responsible for the majority of the variability in these impact results.

Therefore, given that the LCIA methodology is a screening­level assessment of

potential toxicity effects, the results of this study indicate that further investigation

into the leachability of lead from cables disposed of in landfills is warranted, as well

as a more targeted evaluation of exposure and risk of lead leachate from the landfill. 

Beyond the issue of lead, EOL disposition choices for wire and cable products are

complicated by the trade­offs inherent to the processes themselves.  The

sequestration of wire and cable waste by landfilling is not without its source of

potential hazards beyond that of lead.  The release of methane from landfilled resins

impacts global warming potential, and the PVC waste could become, over long periods

of time, a source of other halogenated emissions.  Incineration, while advantageous

from a landfill space use perspective, results in airborne lead emissions, which can

be problematic from a public health standpoint.  Thermoplastic recycling is energyintensive and creates new waste streams, which must then be landfilled.  The choices

42
are not straightforward, and depend, among other things, on regulatory standards,

economic incentives, and the value placed on different environmental burdens.

The uncertainty analysis revealed that several impact categories are sensitive to the

variabilities defined here.  Further refinement of the inventory data and EOL

assumptions that are the subject of the uncertainty analyses would help reduce

uncertainties and lead to more reliable study results.  In addition, LCA results such as

those presented here provide a type of screening analysis where differences across

cables in various impact categories are shown in the context of uncertainty.  In some

instances discernable differences cannot be inferred; however, where more

significant differences are likely (e.g., potential public non­cancer and potential

aquatic ecotoxicity) further refinement is warranted, such as using health risk

assessment techniques to begin to identify human and ecological health risks.

43