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The Working Environment in LCA

2 The new method

2.1 The data format
2.2 A short description of the method
2.3 The impact categories
      2.3.1 The statistical background
      2.3.2 The content of the statistics
2.4 Advantages and disadvantages of the method
      2.4.1 The advantages
      2.4.2 The disadvantages
2.5 The limitations of the method
      2.5.1 Danish statistics
      2.5.2 Supplementary data
      2.5.3 Nickel production as an example of calculations on the company
2.6 The uncertainties of the method
      2.6.1 The level of detail for certain sectors
        2.6.2 Produced amounts in the sectors
2.7 The sensitivity of the method
      2.7.1 Production of raw materials
      2.7.2 Impacts in single companies and on individuals

The new sector assessment method that is presented in the following chapters is seen as a good alternative to the combined sector- and process assessment method described in EDIP97¹. The new method has as its main consequence that it is easier and operational to include the working environment in LCA. It also has the consequence that the level of detail is decreased in comparison with a full assessment made with the combined EDIP97 method. The level of detail is however sufficient to fulfil the basic requirements, i.e. to create an overview of the changes in the working environmental impacts following changes in the life cycle of a product or a product system.

As for the sector assessment in EDIP97, the new method is based on statistical information. The main difference between the two sector assessment methods is that the new method uses the goods statistics to calculate production amounts in the sectors, whereas the EDIP97 method uses the supply statistics, both from Statistics Denmark.

2.1 The data format

In the goods statistics, information on produced amounts (in pieces, tons, m², etc.) can be found along with information on the value of the products. The information has been collected in a way that allows them to be related to specific sectors, as is the case for information on work-related accidents and injuries. The two types of information can then be combined, producing key figures on e.g. “accidents per produced tons” for a number of sectors. The unit for the key figures is basically the same as that for other effect categories in LCA, where e.g. “tons CO²-equivalents per produced tons product” is an expression of the contribution to global warming.

The use of the goods statistics gives the possibility of establishing a homogenous and transparent database for a large number of sectors in Denmark. It is also possible to update the database when new information is available from Statistics Denmark. Furthermore, it will be possible to establish similar information from other countries, as the goods statistics are prepared in the same way in most countries. The main difference from one country to another will then be caused by the differences in the statistical information on work-related accidents and injuries.

2.2 A short description of the method

The main content of the new method is that it is able to calculate the number of reported accidents and injuries per produced weight unit on the sector level. The procedure for the calculations can be described in five steps that are exemplified in section 2.6.2.

The first step is selecting sectors and sub-sectors with a significant number of work-related accidents and diseases. By choosing sectors with a significant impact on the working environment the statistical uncertainty regarding the number of impacts is reduced.

An important criterion is that the sector can be characterised by one or more unit processes that are of interest in relation to LCA. The sector “Production of plastics packaging” (NACE-code 252200) will thus comprise processing of almost all types of plastics using extrusion, injection moulding etc., but it is not possible to achieve a higher level of detail. Another example is the sector “Production and first processing of lead, zinc and tin” (NACE-code 274300) which - as the title indicates - comprise both production and processing of all three materials.

The second step is to identify in the goods statistics the products that are being produced in the selected sectors. The products are identified by an 8-digit code that is unequivocally related to an economic sector. As an example, products made in the sector “Production and first processing of lead, zinc and tin” (NACE-code 274300) all start with the numbers 78 (lead), 79 (zinc) and 80 (tin), respectively.

It is strongly suggested that a professional statistician from a governmental statistical agency perform this step - and the subsequent calculations - with access to the basic statistics given by the companies.

The third step is to produce an aggregate of the produced amount (in tons) for all goods in the chosen sectors. In some cases, when information on the weight of the products is not available, additional information from the foreign trade statistics can be used to calculate the weight of the production. Information from the companies to be used in the foreign trade statistics must contain information on the weight and the value of exported products. The average value per weight unit of the export was therefore used to calculate the (missing) weight of the total production in the goods statistics of a given product by the following equation:

With the additional information from the foreign trade statistics the weight of the produced amount in a sector can be calculated by simple addition. The resulting figure (in tons) is the best estimate of the total amount of products being produced in a given economic sector.

The fourth step is not a calculation, but simply accounting for the work-related injuries and damages for the activities in the same sector as the produced volume was calculated for. As described earlier, the Danish Labour Inspectorate kindly provided this information which can be found at a lower level of detail at their homepage, www.at.dk.

The fifth and final step is to calculate the working environmental impacts per functional unit by dividing the information from step 4 with he information from step 3. The result of this calculation is a figure for the number of work-related accidents and injuries per produced tons. This figure can be used along with figures for other impact categories in the LCA-calculations.

2.3 The impact categories

2.3.1 The statistical background

In Denmark, all notified occupational accidents and occupational diseases are recorded by the Registry of Occupational Injuries, which is a part of the Danish National Labour Inspection Service. The information is treated statistically and is published annually on a 2- or 3-digit DB93/NACE-code level. The Danish National Labour Inspection Service is however able to specify the statistics in more detail upon request, and this detailed information was used in the above procedure.

2.3.2 The content of the statistics

Even though the accidents and diseases are sorted and registered into respectively 15 and 18 different categories only the result of 10 categories are published. The published ones are:

Accidents:

• Fatal accidents
• Other damages from accidents. This effect category is in the statistics subdivided into nine types of damages, e.g. amputations, concussions, wounds and poisonings. The nine types of damages have been aggregated into one category, the main purpose of which is to create an overview of the potential for unwanted and acute incidents.
  

Diseases:

• CNS function disorder
• Hearing damages
• Cancer
• Muscolo-sceletal disorders
• Airway diseases (allergic)
• Airway diseases (non-allergic)
• Skin diseases
• Psycho-social diseases

In order to minimise the statistical uncertainties, an average for the years 1995-1997 is used for both the produced amounts and the accidents/ damages in a sector.

2.4 Advantages and disadvantages of the method

2.4.1 The advantages

The main advantage of the method is that it is able to create an overview of the working environmental impacts of a product in a short time. Inventory data have been established for a large number of unit processes and can be used for calculations in a spreadsheet or a dedicated LCA PC-programme. In comparison with EDIP97 it is not necessary to supplement the data with company specific information, a procedure that is very resource demanding.

By exclusively using a sector assessment it is secured that the database for the assessment is as homogenous as the basic statistical material allows for. At the same time, the potential problems in combining information derived in two different ways in a sector and a process assessment are avoided.

2.4.2 The disadvantages

The main disadvantage of the method is that the level of detail cannot be increased beyond the level allowed by the basic statistical information. This may in practice limit the possibilities for interpretation of the results. This is discussed in the following sections.

2.5 The limitations of the method

The new method has been developed so it can handle all types of unit processes at the same level of detail. There are no formal limitations of the method as seen in relation to the ISO 14040-series, but there are some practical limitations that the LCA-practitioner should be aware of.

2.5.1 Danish statistics

The method is based on Danish statistics on production of goods as well as work-related accidents and injuries. The collection of statistical background material has with a few exceptions been limited to Denmark and the developed database therefore reflect Danish conditions almost exclusively.

A main consequence of this is that the results of a working environmental LCA show the anticipated impacts as if the whole life cycle takes place in Denmark. This is very rarely the case, especially because many raw materials are being produced outside of Denmark. The following general and specific aspects must therefore be considered when interpreting the results.

2.5.1.1 General aspects

The number of reported diseases and accidents is assumably somewhat lower than the actual number. This is a general finding in all sectors and is probably also the case in other countries. 

  The Danish working environmental conditions are presumably better than in many other countries. The use of Danish statistics to account for impacts in other countries will therefore underestimate the impacts. This to some extent counterbalanced by an assumed lower reporting frequency in other countries.

2.5.1.2 Specific aspects

The impacts from production of raw materials have been calculated using statistics on the relatively modest Danish production. This is for example the case for aluminium and steel, where the Danish production is based on secondary aluminium and steel as the basic raw materials. In other countries, primary as well as secondary raw materials are used in the production of the two materials. For plastics, Denmark has a very limited production, and none of the bulk plastics like PP, PE, PS or PVC are produced in Denmark. It should, however, be remarked that plastic production in all countries takes place in the same sector (NACE-code 241600), irrespective of the plastic type being produced.

The main implication of this difference between Danish and foreign production of raw materials is that the representativity of the data used to describe these processes is unknown and therefore an uncertainty is introduced.

This limitation of the method can maybe be reduced if other countries establish corresponding figures using the same procedure. The goods statistics are made following internationally accepted guidelines and are therefore comparable from one country to another. Statistics on work-related accidents and injuries however vary significantly, both with respect to the types of injuries that are reported and with respect to the frequency of reporting. Using foreign trade statistics will thus introduce other types of uncertainties; e.g. it will be difficult to aggregate all effect categories over the whole life cycle.

2.5.2 Supplementary data

During the establishment of the database it was tried to create a broad overview by finding the outlined information for about 75 economic activities in different sectors. The activities have been selected on the basis of their relevance for LCA in general (“the most common processes”) as well as the statistical background material. The latter means in practice that some sectors have been omitted because the number of reported diseases/accidents is very small, leading to a large statistical uncertainty.

There are, however, still a number of activities or unit processes that is not covered in the database. If data are missing on processes that are assumed to be important, it is recommended that the LCA-practitioner establish his own information on these key processes, for example with help from Statistics Denmark. This could for example be the case for economic activities, where

the practitioner judges that the actual impacts differ significantly from the average values given in the database.

Another area where an alternative procedure is necessary is in the sectors where the basic method cannot be applied. This is for example the case for the sectors “Surface treatment of metal” (DB93/NACE-code 285100) and “Textile finishing” (DB93/NACE-code 173000) where the calculation of produced amounts and their value follows guidelines that are different from those for other sectors. It has not been possible to describe a procedure for such sectors within the current project.

For some activities like production of basic raw materials it is possible to extract the requested information from the annual report from Danish or foreign companies. An example is given in the next section.

The example shows that key information is relatively easy to obtain through public available information sources. The example also shows that the level of detail is relatively low. The company does not publish the number of reported diseases and in order to include this information in a LCA, collection of supplementary information is required.

It has not been possible to specify a procedure for such collection. It is suggested that the first step is to search for key institutions and persons on the home page of the Finnish Institute of Occupational Health and Safety (http://www.occuphealth.fi/e/eu/haste/index.htm) that contains an overview of statistical sources for a number of countries. Due to differences in reporting requirements and formats it will, however, often be difficult to obtain a level of detail that matches the present database.

The LCA-practitioner must also be aware of another problem when using the foreign data in the database, namely the representativity. In the case outlined in the present section, information from one year only has been used to establish the information. This means that variations from one year to another are not reflected in the figures for the activity. It can be seen in the technical report that the variation is about 25% for accidents, while it is 100% for fatal accidents (the number of fatal accidents vary between zero and four for three consecutive years).

The representativity of the figures for nickel production on the global scale is also unknown. The producer in the example, WMC, has implemented a number of safety measures, but still has a relatively high accident frequency. Other countries (especially developing countries) and specific companies may have a less effective safety policy that can lead to a significantly higher accident frequency. However, the opposite may also be the case.

2.5.3 Nickel production as an example of calculations on the company level

As an example of using company specific information, the magnitude of the working environmental impacts can be derived from the annual reports from WMC, an Australian producer of metals, fertilisers and other products.

The combined “Lost time and Medically treated injury frequency rate” (LMI) was in average for all WMC operations 30.7 per million hours worked in 1996-1997. For the nickel operations, the average figure was 34.7 with a range from 6.1 to 54.0 in different operations.

The production in 1996-1997 was 47.600 tonnes and the labour productivity was stated to be 37 tonnes of nickel metal produced per employee in the same year. Assuming that each employee works 2000 hours per year, the LMI per tons nickel can then be calculated to

((34.7 * 10^-6) * (2000/37) »1.9 * 10^-3 injuries per tons nickel.

There were two fatal accidents in the nickel operations in 1997 in WMC. With a production volume of 48.000 tonnes the number of fatal accidents per kg nickel can be calculated to 2/48.000 kg »4*10^-5 fatality per kg nickel.

2.6 The uncertainties of the method

As indicated in the previous sections, the described method is associated with some uncertainties. Two of the most important issues in this context are addressed in the following sections.

2.6.1 The level of detail for certain sectors

One of the starting points for choosing the sectors to be included in the database was the EDIP PC-tool, simply because a main goal was to find statistical information on the working environment for the same processes that are contained in the database. Neither the statistics on work-related accidents nor the goods statistics do however give the possibility of matching the level of detail in the EDIP PC-tool. It should be noted in this context that a satisfying level of detail is required for both types of information in order to reach the desired result.

The consequence of this is that most sectors will be assessed by using average figures for the sector as whole, and not by using figures for specific processes. As an example, the working environmental impacts are the same for extrusion of one kilo of PE-sheets as for injection moulding of one kilo of ABS-crates. The reason for this is that both activities takes place in the same sector, ”Production of plastic packaging” (DB93/NACE-code 252200). Likewise, it is not possible to distinguish between the impacts from production of lead and production of zinc, and a subsequent processing of the materials. In this case, the statistics on work-related accidents and injuries is the limiting factor, because the goods statistics has the possibility of distinguishing between the two materials.

  2.6.2 Produced amounts in the sectors

The procedure for calculating the produced amounts in the single sectors may also introduce some uncertainties.

The total amount produced in a sector – measured in a weight unit – is one of the two parts of the equation used for calculating the impacts per tons. For some sectors, information on the weight of the products is available in the goods statistics for all products, whereas for other sectors, the produced amount is stated in m2, rolls, etc. In these cases, the weight must be estimated using foreign trade statistics. This procedure can best be illustrated by an example where a number of goods being produced are used for the calculations. As can be seen in Table 1, there is information on both the amount and the value for some products, while for others only information on the value is available.

Table 1. Example of basic statistical information used in the calculation of produced amounts in a sector

The total production can be calculated by the following procedure:

(1) For the products with the missing information in tons, the average value per weight unit (kr/tons) is calculated from the foreign trade statistics, where both information on value and weight is available.

(2) The total production (in tons) for the product is calculated by dividing the value of the product (from the goods statistics) with the average value per weight (calculated from the foreign trade statistics in (1) ).

(3) The total production for that sector is calculated by simple addition of the production for each product.

The uncertainty that is introduced in this calculation is that the average value per weight unit used in the foreign trade statistics (export/import) may not be the same value as used in the goods statistics. Even though it is exactly the same products, the price may differ from the home market to the export market. The average value per weight unit from the foreign trade statistics may therefore be over- or underestimated, causing some uncertainty regarding the produced amount. However, the results from all sectors are based on a comprehensive statistical basis, i.e. many products are used in the calculations, and the potential uncertainty is therefore in general regarded as low.

An example is the steel producing sector where the calculated and measured (Jernkontoret, 1999) amounts in the steel producing sector for two years are  compared in the table below. As can be seen from the table, the difference between the two values is at most about 5%.

Table 2. Comparison of calculated and actual production in the steel sector

In other sectors, the number of products where information on both price and weight is available is smaller. This is most pronounced in sectors with a high degree of wage work, e.g. in textile processing. For this sector, use of foreign trade statistics has been essential, giving a rather high uncertainty, and the results from these two sectors should be used with great caution. For surface treatment, another sector with a high degree of wage work, the amount of available data was so small that the results most probably would be misleading. This sector is therefore omitted from the database.

In very few sectors the goods statistics could not be used for the calculations because of confidentiality restrictions. This is the case for “Production of rock wool” (DB93/NACE-code 268220) where the number of companies in the sector in Denmark is so small that Statistics Denmark is obliged to keep the production figures confidential.

The actual magnitude of the uncertainties caused by the statistical limitations cannot be assessed precisely. The uncertainty may amount to a factor 10 or more in extreme cases, but the uncertainty will generally be comparable to that found in effect categories like human toxicity and ecotoxicity.

2.7 The sensitivity of the method

The results achieved by using the method are sensitive for variations in the basic statistical data and the applied calculations. This can to some extent be compensated for in a specific LCA by choosing a set of data from the database that covers the actual activity in the best possible way. The following sections show some of the limitations and possibilities associated with the database.

2.7.1 Production of raw materials

Production of raw materials is – like other processes – described by using Danish information. This may cause some practical problems, as many basic raw materials are not produced in Denmark.

2.7.1.1 Data for secondary raw materials

In order to be able to include production of raw materials in the LCA, data for production of secondary raw materials in Denmark have been established. Both the production volume and the number of accidents and injuries in these sectors are small, and the calculations of accidents/injuries per produced unit are accordingly associated with a relatively large uncertainty.

2.7.1.2 An alternative calculation method

As an alternative, the impacts from production of a few metals from metal ore have been calculated. The calculations are documented in full in the technical report, and an example is shown in section 2.5.3. The examples show that it is possible to use annual reports from companies to derive the requested information, although the precision and representativity is not of the same quality.

2.7.1.3 Only accidents included

A major difference between company specific data and the Danish average data is that company specific information generally only concern accidents and fatal accidents. When the information from several activities in the life cycle of a product are aggregated this will give some black spots in the calculations, i.e. that the contribution to other effect categories will be underestimated. One example is that mining of metal ore has a large impact with respect to hearing damages and lung diseases, but this will not be included in the results.

2.7.2 Impacts in single companies and on individuals

2.7.2.1 Single companies

The basic statistics used in the method gives an average assessment of the impacts per produced unit of a material or product. It is obvious that in real life there will be a wide variation in the impacts in single companies because of differences in the product-, material- and process portfolio as well as the internal management of the working environment. Using the method cannot reflect this variation.

This also means that it is not possible to assess the changes in the working environmental impacts following changes in the choice of e.g. processes and materials. The best way to examine such changes is by performing work place assessments that specifically has the aim of mapping the impacts in a given process and to prioritise the efforts that are necessary to make the working conditions satisfactory. If a company has a certified working environmental management system it is ensured that the company fulfils all legal requirements and that the company is devoted to a continuous effort to prevent working place injuries on both the short and long term.

Another inherent issue (or problem) is using the algorithm of the method is the connection between impacts and produced amounts. It is obvious that with an unchanged number of accidents and injuries an increase in the produced amounts will lead to a smaller number of impacts per produced unit.

Individuals who are producing larger amounts because of an increase in the work intensity will however not experience this as an improvement of the working environmental conditions, rather on the contrary. The risk of accidents, an impaired psycho-social working environment and an increase in repeated monotonous work will often be the result of an increased working intensity, but this is not reflected in the method.

Footnotes

¹ “EDIP97” is in the present report a common denominator for the methodology descriptions that can be found in Hauschild (ed.): Baggrund for Miljøvurdering af produkter, Miljøstyrelsen/Dansk Industri 1996, (English version: Hauschild and Wenzel: Environmental Assessment of products. Volume 2: Scientific background. Chapman & Hall, 1997), Wenzel, Hauschild and Rasmussen: Miljøvurdering af produkter, Miljøstyrelsen/Dansk Industri 1996, and in Broberg og Rasmussen: Arbejdsmiljø fra vugge til grav, Arbejdsmiljøfondet 1996.

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Version 1.0 December 2004, © Danish Environmental Protection Agency