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LCA and the Working Environment 2 The new methodologyIn short, the new methodology is a sector assessment method; i.e. it uses different kinds of statistical information from economic sectors to produce product specific information regarding the working environmental impacts per functional unit. The procedure for performing LCA-calculations including the working environment does not differ from the general procedure in LCA, and the description of the methodology therefore has its main focus on how the database has been developed and how the associated uncertainties can be handled. The first sections (2.1-2.8) in the chapter describe the development of the general database, while section 2.4 describes the development of the database for those sectors, where the general methodology could not be applied. 2.1 Statistical sourcesThe general methodology uses two types of statistical information to derive the database:
2.1.1 Work-related injuries and damagesIn 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 registers contain information that identifies the reports and the injured persons and enterprises involved. This information describes the work function, the accident event/the exposure sources that led to the occupational disease, the type of injury, a diagnosis, and a number of other background factors. Danish employers are required to notify all occupational accidents and cases of toxic injury which results in one or more days' absence from work. In addition, doctors and dentists are required to notify all work-related diseases, even merely suspected cases. An "occupational accident" is an injury sustained by persons on account of their work, where the event causing the injury
Likewise, an "occupational disease" is an injury sustained by persons on account of their work, or on account of the conditions under which work takes place
However, some diseases may manifest themselves suddenly even though they may be due to long-term exposure. All occupational diseases occurring to persons performing work in the service of Danish employers and at Danish workplaces in Denmark, are included. But when it comes to occupational accidents only persons employed at Danish workplaces in Denmark on land are included, leaving out the accidents occurring at sea or in the air. Even though the accidents and diseases are sorted and registered into respectively 15 and 18 different categories only the result of 9 categories are published. The published ones are: Accidents:
Diseases:
The statistical information on work-related damages and injuries can be assumed to be most precise (or statistically representative) for those sectors where the reporting is most intensive, simply because large numbers can be taken as an indication of a large economic activity and/or a relatively high impact in the working environment. As a consequence, it is suggested that the statistics on work-related injuries and damages is used to select the sub-sectors for which the calculations can be performed with a relatively high degree of prediction power. The procedure should ideally exclude calculations for sub-sectors, where the reported number of damages and injuries is small, for example less than 15 per year, but this rule of thumb must be disregarded in some cases, where more representative data cannot be found. 2.1.2 Produced amountsThe information on the produced amounts can be derived from the Danish statistics on goods production (Varestatistik for Industri), which is published four times a year, the last publication for each year containing aggregate information for the whole year. The Danish statistics on goods production is based on a questionnaire produced by Statistics Denmark. The questionnaire is sent out to all industrial companies with more than 10 employees and includes questions of what the company produces, the value of the produced goods and some kind of quantity unit for it (tons, meters, pieces etc.). Value is the only parameter that is common for all the trades. By combining the result from the questionnaires with the statistics for the foreign trade, it is thus possible to convert all the amounts of produced goods to a weight unit, no matter what they prior was given in. The uncertainty introduced by this procedure which is described in detail in section 2.3.3-2.3.5 depends on the homogeneity of the products being produced in the sector. For one sector, production of steel, it has been possible to compare the results of the calculations using the outlined methodology to the actual production as stated by Jernkontoret (Jernkontoret, 1998). A comparison for the years 1996 and 1997 is shown below. Table 2.2 Comparison of produced and calculated amounts for two years in the steel producing sector.
The statistical information in the publication series is for many sectors grouped in a way that directly matches the information on work-related injuries and damages for the same sectors. Examples are:
For other sub-sectors it is more difficult to establish a direct relation between the two types of information that is required by the methodology, for example processing of iron, steel and plastics. With a careful examination of the products groups in the goods statistics, however, it should be possible to establish the information also for such sub-sectors with a relatively high degree of precision. Consultation with professional statisticians, e.g. in Statistics Denmark, is very helpful in these cases as the Agency possesses the basic statistical information as well as the key for allocation of product groups to economic sectors. 2.2 Combining the statisticsBy combining the two statistical sources it is possible to relate the working environmental impacts to the unit processes commonly used in LCA and thereby create an operational tool for including the working environment in LCA. Before it can be done, however, some assumptions and intermediate calculations have to be established. A basic assumption in the methodology is that the added value from a given activity is directly related to amount of produced or processed material. At the specific sector level, the results will be an average of many companies, and the information is therefore comparable with respect to representativity to that regarding work-related damages and injuries which is also an average from many companies within a given sector. The assumption is however not always valid at the company level, e.g. companies using highly technological processes to produce small products (example: contact lenses) will differ significantly from companies using comparatively low-level technology to produce mass products (example: packaging products). The main prerequisite for performing and using the calculations is that the products or production in specific sectors can be described in relatively precise terms. This is not always possible on the overall sector level, and when extending the results from one sub-sector to another, it is therefore necessary to assume that the sub-sector activities for which the information is available are representative for the whole sector. It should also be borne in mind, that the products being produced in sectors with a large number of accidents and injuries also tend to be more heterogeneous, the building industry being an obvious exception from this rule of thumb. Thus, in the first and second steps in the following procedure there will always be a trade-off between the specificity of information in the two types of statistics. The practical problems in choosing relevant sectors is, however, not very big as one or both statistical sources in general set the limits on the level of detail that can be achieved. 2.3 The five step procedureThe procedure used in establishing the database can be described in five steps:
2.3.1 Selection of sectorsThe 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. 2.3.1.1 The choices made by the project group The project group identified from the working environmental statistics about 80 sectors with a product profile that was assumed of general interest in relation to many product LCA's. Only a few of these sectors were not suited for the calculations in the methodology, e.g. because the amount of produced goods was not available due to confidentiality like in the case of rock wool. Other sectors like electricity production and transportation required slightly different calculation methods because of differences in the physical units for these sectors (kWh, ton-kilometres). The full database is documented in Appendix 1 to the report. Each sector is described by the NACE-code for the main economic activity and one or a few keywords for the products being produced within the sector is given. When using the database in specific LCA case studies, it may not always be possible to find information about the impacts from specific processes or materials. In such cases, it should be examined whether it is possible to use the procedure outlined in the following paragraphs. If this for one reason or another is not possible, it is recommended that the LCA practitioner uses the information from a sector with a working environmental profile which is assumed to be similar to the sector in question. Another option is to omit the impacts from the given activity. No matter which option is chosen, it is important to address the associated uncertainty when reporting. 2.3.2 Specifying the production in the sectorThe 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, which 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 this step - and the subsequent calculations in paragraphs 3.3.3 is performed by a professional statistician from a governmental statistical agency with access to the basic statistics given by the companies. 2.3.3 Calculating the total weight of the produced amount in a sectorThe third step is to produce an aggregate of the produced amounts (in tons) for all goods in the chosen sectors. The basic information in the good statistics is exemplified in Table 2.3. Table 2.3. Example of basic statistical information used in the calculation of produced amounts in a sector.
When information on the weight of the products was not available, e.g. as indicated by the questionmarks in Table 2.3, additional information from the foreign trade statistics was 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 thus 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. 2.3.4 Accounting for the working environmental impactsThe forth 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. 2.3.5 Calculating the impacts per functional unit (weight)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. 2.4 Supplementing the databaseAlthough the published database is extensive, a LCA practitioner may have additional needs when making an LCA - a need which cannot always be covered by using the methodology outlined in the previous sections. Therefore, methods for supplementing the database are outlined in the following paragraphs, including some examples. The examples are included in the database, but it is stressed that they differ significantly in quality from those developed by the general methodology. 2.4.1 Danish electricity productionOne of the products most commonly used in LCA is electricity and it is a common finding that use of electricity causes significant environmental impacts. The case studies in EDIP97 showed that electricity production also has a significant impact in the working environment, and it is therefore of great interest to make a reliable inventory for electricity production. The inventory for electricity production (e.g. 1 kWh) was produced by calculating figures for production of each of the raw materials (e.g. coal, oil and natural gas) necessary to produce 1 kWh in Denmark and add these to the figures for the production at the Danish power plants. In the context of Danish electricity production the impacts associated with coal production are very important. However, it was not possible within the frames of the project to establish an average set of figures on coal production by using information from all the countries supplying coal to Denmark. Instead, American statistics regarding the amounts of coal produced and the injuries associated with this were obtained from the Mine Safety and Health Administration (MSHA) which is a part of the United States Department of Labour. The production statistics comprise both open mines and pit mines, and the statistics on accidents include all persons involved in coal production from the mine to the production plant. It should be noted that these statistics excludes work-related diseases. When interpreting LCAs in which electricity plays a role, it should thus be remembered that the impacts from electricity production most probably are underestimated. Firstly, the only impacts considered are accidents. Secondly, American coal production is probably associated with fewer accidents (and other impacts) than production in less developed countries like East European countries, South Africa and South America. No efforts have been devoted to describe the differences between the coal producing countries. 2.4.2 Danish transportationTransportation is often regarded a priori as a key issue in many LCAs but the results rarely reflect the alleged importance. With respect to the working environment, transportation is also interesting, mainly because of the risk of accidents but also because of the general working conditions in the sector. In this project, the number of working environmental accidents is calculated for transport by truck, ship and railway. Key figures for amounts of transported goods were found in publications from Statistics Denmark and the Danish Ministry of Transport. These key figures are published every year and an average from 1995 to 1997 was used for the calculations. 2.4.2.1 Units used The unit used for describing working environmental impacts in truck and railway transportation is "impacts per tonne-kilometre" (e.g. the number of accidents caused by the transportation of one tonne one kilometre), which is the same unit being used in calculations of environmental impacts. For transport by ship only the total weight of goods being transported can be found, and the impacts are therefore calculated per tonne transported, not per tonne-kilometre. 2.4.2.2 Transport by truck The amount of tonne-kilometres transported by truck used in the calculations is the national and international transportation with Danish trucks. This information matches the reported number of accidents and diseases connected to these transports. The information includes both transportation on the road and handling of goods in terminals. 2.4.2.3 Transport by railway In the calculations for transport by railway, only transported amounts within Denmark are considered. This information corresponds to the number of accidents and injuries reported to the Danish Labour Inspectorate, assuming that Danish railway workers do not ride the trains to other countries. 2.4.2.4 Transportation on ships For transportation on ships, the amounts loaded in Danish harbours are considered in the calculations. This information is matched with the number of accidents and injuries reported to the Danish Maritime Authority. In doing so, a potential error is introduced because of the following three factors. Firstly, it is not known how much of the loaded goods that is transported with foreign ships. Secondly, the number of reported accidents and injuries comprise all Danish ships, irrespective their routes. This means that accidents on Danish ships sailing on foreign routes are included in the number. Thirdly, the number of accidents and injuries used in the calculation comprises both trade and passenger ships, simply because the latter most commonly transport goods as well as passengers at the same time. The magnitude of the potential error has not been estimated. 2.4.3 Production outside of DenmarkProduction of basic raw materials like primary metals do not take place in Denmark and it is therefore necessary to find other data sources from relevant countries or companies. Most often the information on working environmental impacts will be in the format "Accidents/injuries per 100.000 working hours", "Lost time injury frequency rate" or "Combined Lost time and Medically treated injury frequency rate". Usually, the figures are aggregated and averaged for a number of production facilities or for the sector as a whole in a given country. In order to reach the data format used in the general methodology this information must be related to the production efficiency, i.e. produced amount per man-hour. These figures can in many cases be derived from annual reports from relevant companies, and the final calculations can be performed without significant problems. One should however be aware that by using company specific statistics, other types of uncertainties are introduced, e.g. regarding the representativity of the information. 2.4.3.1 Nickel production as an example As an example, 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. It is also possible to derive the corresponding figures for 1996 by combining the information in the WMC Annual Report from 1996 and 1997:
From this information it can be calculated that the LMI per kg nickel = (37.6*10-6)*2000/30 2.5 injuries*10-3/ tons nickel. The number of fatal accidents per kg nickel can be calculated to 1/47.000 2*10-5 fatality per tons nickel. It is obvious that using information from one company alone is associated with uncertainties. It can be seen from the figures that the number of injuries per kg nickel has decreased from 1996 to 1997. The decrease is caused by an improvement in productivity (23%) and a decrease in the LMI-index (7%). There is thus a variance of at least 25% from one year to another with respect to LMI. For fatal accidents, the incidence rate may vary even more, from zero to 1*10-4 fatal accidents per tons nickel (or even more). The number of injuries and accidents, especially fatal accidents, that is derived in this way should therefore be used only as a crude measure, until a more reliable average can be established. Besides the variations described above, additional uncertainties are associated with the number of working hours per year per employee and the production volume. In the example, parts of the nickel operation were shut down during periods of time. The number of working hours may therefore be overestimated. At the same time, the intermediate product "Nickel in concentrate" was sold at the international spot market in order to limit stock piling. It is however not possible to deduct from the annual reports if this is reflected in the overall statistics. The largest uncertainty is associated with the unknown representativity of the company used in the example. This is discussed further in section 2.4.4. 2.4.3.2 Gold as an example WMC is also a gold producer. In 1997, 529 employees produced 21.838 kg (770.305 ounces) of gold. The Lost time and Medically treated injuries (LMI) per million hours was 48.2 in the gold production. Assuming that each employee worked 2000 hours in 1997, the figure for injuries per kg gold can be calculated: (529*2000*(48.2*10-6))/21.838 2.3 injuries per tons gold. In 1996, the Lost time and Medically treated Injuries per million hours in the gold operation was 68.7. The number of employees was 876 and the production was 22.787 kg. Using the same procedure and assumptions as for 1997, the corresponding figures can be calculated to 5 injuries per ton gold, i.e. twice as many injuries as in 1997. No fatal accidents were reported for the gold operations in 1997, while there in 1995 were three fatalities and one fatality in 1996 in gold production in WMC operations. It is therefore suggested to calculate an average value, i.e. for the years 1995-1997 1.33 fatal accidents were observed in average. Using this average, an estimate of the number of fatal accidents per tons gold can be calculated to 1.33/22.312 6 * 10-2 fatal accident per ton gold. It should be noted that the average production is calculated using only information from 1996 and 1997. 2.4.3.3 Copper and uranium as an example At WMC there is an integrated production of copper and uranium and the working environmental impacts are reported as one figure for both productions. It is however possible to allocate the impacts according to the economic value of the two products and thereby achieve a figure for each of the materials. The necessary data and the calculation procedure is outlined in some detail in the following:
The basic formula for allocation of the injuries is:
Entering the above figures gives the following formula:
Using the same procedure and the same basic data, the number of injuries per kg uranium can be calculated:
2.4.3.4 Steel production as an example The figures for Danish steel production in the database have been supplemented with figures on Swedish steel production. Sweden produces a large amount of crude steel from both virgin and recycled materials and at the same time the Swedish procedure and traditions for registration of work-related injuries are fairly similar to the Danish procedure. The information on the amounts of produced steel (4.91 million tons) was obtained from "Jernkontoret" - the Swedish Steel Producers Association (www.jernkontoret.se). The information on work related injuries was obtained from ISA – the Swedish Agency for work related injuries (ISA, 1996). The figures from the two sources are not fully comparable, because Jernkontoret specifies the total number of employees as well as the total production of steel in Sweden, including the production in sectors outside the NACE-code for this process (271000). It is not possible to distribute neither the number of employees nor the amounts produced on sub-sectors. In contrast to the information from Jernkontoret, the ISA-statistics on work related injuries only concern the employees in the specific sector. To account for this difference in the basic statistics the production figures from Jernkontoret have been reduced with a factor 1.54, reflecting the relation between the number of persons producing the steel in the production statistics (21.000 persons) and the number of persons employed in the sector included in the ISA-statistics (13.663 persons). The basic assumption behind this is that the frequency of injuries and accidents is the same in the primary sector (NACE-code 271000) and the other sectors producing steel. 2.4.4 Representativity, completeness and p recision2.4.4.1 Representativity It is obvious that the figures for nickel gold, copper and uranium production are associated with a large uncertainty regarding their representativity for use in LCA. The most prominent example is probably that it can be assumed that there are large differences between the working environment in industrialised countries and in developing countries. When using information from industrialised countries, it is therefore almost certain that they will be an underestimate of the average working-related injuries at the Global level. The figures on steel production are assumed to be representative for modern steel production. There may however still be large differences between single companies in Sweden and there will probably be even larger differences to countries with less modern production facilities and less focus on the working environment. The outlined procedure for establishing inventory data is very simple once relevant data sources have been identified, and it is often possible to obtain data for several years from the same source and thereby produce more reliable averages for the given company or country. It will often also be possible to obtain information from several companies and countries and thereby establish ranges for the working environmental impacts per produced unit. 2.4.4.2 Completeness It should be noticed that the information from the specific producer (WMC) only regards the number of accidents and injuries and not reported damages and diseases following (long-term) exposure. It is a well known fact that employees in the mining industry are exposed to high levels of e.g. noise and hazardous chemicals and it can therefore be expected that a more detailed examination of the health records at the company will show a relatively high incidence rate. This information was not available to the project group, but may eventually be obtained from official statistical sources. 2.4.4.3 Precision Based on the previous paragraphs it can be concluded that the precision in the inventories for productions outside of Denmark is relatively low. The most serious concern is that reported diseases and damages are not included in the inventory and the overall impacts from this type of production are significantly underestimated. In the end, the need for precision will always be balanced by the resources needed to provide the information. It is therefore suggested that the figures derived from foreign sources primarily are used as a first indicator in a LCA. If e.g. nickel mining and further production proves to be important in the LCA, LCA consultants or companies are advised to seek more precise information from the actual supplier or to establish a broader overview of the working environmental impacts. 2.5 The resulting databaseThe resulting database from the calculations is presented in Chapter 9. The 80 sectors in the database are grouped according to the following headlines:
It should be noted that the general headlines reflect a wide variety in the state of the products. The production within a sector may thus comprise both semi-manufactured goods for further processing, components for assembly with other components into final products and final consumer products. With the 80 unit processes in the database the need for information can be covered in some detail for many of the LCAs that are being made today. One should however be aware that the database is not homogenous with respect to the activities taking place inside and outside Denmark. This is discussed further in section 2.4.4. This is especially the case for the production of virgin metals, where the only impacts described are the number of accidents. Furthermore, the impacts have generally been calculated using company-specific information with an unknown representativity. Another example is production of coal, where average American conditions have been used for the calculations. Again, the level of detail with respect to the working environmental impacts is low compared to the other sectors in the database, and the representativity is unknown.
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