Health and Safety
Executive / Commission
Regulatory Impact Assessments: Chemicals
1. Phenol is included in a Commission Directive on Indicative Occupational Exposure Limit Values (IOELVs). Member States are required to have set a national occupational exposure limit for phenol that takes into account the IOELV by 31 December 2001. This implementation date necessitates a proposal to ACTS at its July 2000 meeting.
2. The IOELV for phenol is 2 ppm (8-hour Time-Weighted Average (TWA)) and a 'Skin' notation is assigned. This proposal is based on a recommendation made by the EU Scientific Experts Group (SEG) in 1992. This position was developed for DGV by the Danish Technological Institute in 1991 and was used by HSE as the basis of its general review.
3. The objective of the proposals is to reduce occupational exposure to phenol by the setting of a single Maximum Exposure Limit (MEL), both an 8-hour and a 15 minute TWA. This document will inform ACTS as to the financial consequences of this procedure.
4. Phenol was already on the WATCH/ACTS programme because of concerns about its mutagenicity. A package on Phenol was first brought to WATCH in September 1993. The advice of the UK Committee on Mutagenicity (COM) was sought because of uncertainties identified at WATCH in the assessment of the genotoxicity data for phenol.
5. Phenol, together with the closely related substance hydroquinone, was discussed at a number of meetings of the COM, which concluded in October 1999 that "the available data showed that occupational exposure to phenol was associated with a risk of mutagenicity but it was not possible to quantify this risk".
6. In view of the COM conclusion, WATCH agreed that it would not be appropriate to recommend an OES for phenol, and as the lead health effect is genotoxicity, a MEL was felt to be warranted. WATCH was asked its opinion on the perceived risks to health arising from exposure at the IOELV of 2 ppm, 8-hour TWA. The WATCH view was that there were no strong scientific reasons to suggest the need for the value of the 8-hour TWA to lie below 2 ppm given that phenol did not appear to be a particularly potent genotoxicant.
Supply and transportation
7. Phenol is normally stored and transported in the molten phase at temperatures between 50oC and 60oC. Phenol is unloaded from ships and transported in road tankers. Warm phenol is routinely pumped from tankers into storage for a range of purposes. Thus, whilst phenol is being distributed there is potential for exposure during the coupling and uncoupling of lines. These exposures are normally short and will rarely exceed 5 ppm.
Chemical synthesis
8. Phenol is used as a starting material in the synthesis of a range of chemicals. The main products are phenolic resins which themselves have a wide range of uses. The chemical is used in closed vessels and significant inhalation exposure is only likely where the reaction vessels need to be opened during planned or unplanned maintenance. Acid-proof suits and RPE are used for these tasks. The numbers of workers exposed at these sites is small.
Paint stripping
9. The main dispersive use of phenol is in specialist paint stripping. It is used where a particularly effective formulation is required, such as in aircraft paint stripping. Special hangars with extraction ventilation are commonly used. As the paint stripper contains dichloromethane (DCM) as well as phenol, control measures put in place to control exposure to DCM will provide good control of the phenol exposure and task-based levels will rarely exceed 2 ppm.
10. There are three main companies and several smaller companies involved in paint stripping on a regular basis and the total personnel involved numbers about 200. On average, each employee will spend about 60 days per year exposed to phenol but the average shift time could be around 10 hours.
Use of phenolic resins
11. Phenolic resins are widely used in the UK. These resins contain varying amounts of free phenol and many thousands of employees are potentially exposed to low concentrations of phenol. We have assumed that 40,000 employees are potentially exposed.
Sand-coating and the use of phenolic resins in foundries
12. Many foundries use phenolic resins to bind together moulds and cores, but local exhaust extraction is usually on the smaller products. For floor casting, control is more difficult to achieve, relying on captor hoods for the permanent casting positions and general ventilation elsewhere. During casting, phenol is released as a thermal breakdown product. About 50% of the personnel in foundries are likely to be exposed to phenol which could add up to 33,000 employees. Exposure to phenol will be intermittent and will rarely exceed 2 ppm for the duration of the task involved.
Dermal absorption
13. Phenol is readily absorbed through the skin and the control of dermal exposure is an important consideration. Throughout the supply chain phenol is handled as a molten liquid at 50-60oC. Due to the seriousness of contact with hot molten phenol, good systems of work are necessary and suitable PPE is always used. However, there is the potential for occasional contact with surfaces contaminated with phenol arising from drips and spills.
14. A summary of all the available measured inhalation data is given in Table 1.
Table 1. Phenol inhalation data
| Task | number of samples | Range of samples (ppm) | Number of samples above 2 ppm |
|---|---|---|---|
| Paint stripping | 43 | <0.1 - 4.5 | 7 |
| Sand coating | 48 | <0.1 - 4.4 | 1 |
| Foundry use | 64 | <0.1 - 6.5 | 6 |
| Miscellaneous | 34 | <0.1 - 2.7 | 1 |
15. These exposure levels are task-based and not converted to TWAs. However in some situations, like foundries, where the work pattern is more homogeneous, the task-based exposures are likely to be similar to the overall 8-hour TWAs.
16. A summary of the predicted values from EASE for some tasks is given in table 2.
Table 2. Predicted inhalation exposure to phenol
| Task | predicted TWA over 8 hour reference period (ppm) | Predicted TWA over 15 min reference period (ppm) |
|---|---|---|
| Phenol distribution | - | 0.7 - 6 |
| Chemical intermediate | <0.1 - 0.25 | <0.1 - 0.5 |
| Resin production | <0.1 - 0.3 | 0.5 - 5 |
| Production of friction material for brake pads | 0.0025 - 0.25 | 0.0025 - 0.25 |
17. For the purposes of comparison it was chosen to analyse MELs (8-hour TWA) at the following levels of exposure:
18. The following organisations were contacted for information:
19. Visits were also made to an aircraft paint stripping company, a foundry, several producers of phenol and phenolic resins, a sand coating company and a manufacturer of brake pads.
20. Costs and benefits of this regulation are calculated over the appraisal period 2001/2 - 2010/11 and are expressed in net present terms. In arriving at ten year cost figures two adjustments are made. Firstly, earnings are assumed to rise by 1.8% per year in real terms which is the observed increase for the whole economy over the past twenty-five years or so. Secondly, costs are discounted to present value using the Treasury recommended 6% discount rate.
21. There are few people exposed to phenol as a chemical starting material but very many are exposed to varying concentrations of free phenol from the resins which are ubiquitous. In total it is estimated that between 70,000 and 80,000 people may be exposed to phenol in its different forms in the workplace. The lead health effect of concern for phenol is genotoxicity.
22. Animal studies indicate that phenol is of moderate acute toxicity. The Department of Health Committee on Mutagenicity has considered the available mutagenicity data for phenol and concluded that "occupational exposure to phenol is associated with a risk of mutagenicity, but it is not possible to quantify this risk." There are no human studies available on the genotoxicity of phenol but available epidemiological studies investigating the carcinogenic potential of phenol to humans are complicated by the lack of adequate exposure data for phenol, and therefore no reliable conclusions can be drawn from them.
23. Thus, there is insufficient data to determine the cases affected and work days lost due to illness from exposure to phenol ie no dose-response relationship for the mutagenic effects of phenol exists. However, a reduction in exposure is likely to reduce the risk of any mutagenic effects.
24. The business sectors affected were divided into separate categories.
Supply and transportation
25. Phenol is imported from Europe at about five sites across the UK. Ship to shore transport is via flexible hose into specialised storage vessels (heated by steam coils). A ship may contain up to 3,000 tonnes of phenol and the pumping rate is less than 300 tonnes an hour so it may take a full shift for a boat to be fully unloaded. From the storage tanks at the port, the phenol is top loaded, with a vapour scrubber, into dedicated road tankers. Full chemical PPE is specified for these tasks.
26. Road tankers run to many sites within the UK and off load through the usual coupling methods into storage on site. It is difficult to be specific about the numbers of workers involved as the business is variable but we have assumed about 250.
Chemical synthesis
27. About six companies employing fewer than 100 employees use phenol to manufacture a variety of chemicals such as agrochemicals, flame retardants and pharmaceuticals. There are about the same number of companies (and employees) who are involved in the manufacture of phenolic resins. Exposure is restricted by the enclosed nature of the reactions.
Chemical paint stripping
28. A small group of workers is involved in this process, totalling about 200. The usual pattern is for 12 hour shifts to be worked, during which about 10 hours involved exposure to phenol, present in a concentration of up to 25% in the formulation. Approximately 60 days annually are spent where phenol is present. PPE is routine and cannisters are used rather than airline RPE to enable easy access to various parts of the plane.
Usage of phenolic resins
29. There are a large number of sites in UK using phenolic resins for a variety of purposes. Although these uses represent the great majority of potential exposures, about 85,000 tonnes of phenol are used annually for the production of these chemicals, the exposures tend to be low because of the low level of free phenol involved. It is difficult to estimate the total numbers exposed because of the large number of uses and small companies involved but we have assumed about 40,000.
Sandcoating and the use of phenolic resins in foundries
30. There are about 600 foundries that are members of the British Foundries Association and perhaps another 300 small foundries, which may have fewer than 5 employees. Total numbers employed are about 65,000 with a maximum of half of them exposed to phenol. 90% of the foundries use sand casting but the very large ones may use green sand alone. The sandcoating companies are few and the number of employees exposed is less than 200.
31. For each business sector affected the extra control costs will be calculated for both potential MEL values. Although costs are calculated for each sector separately some costs are common to both potential MELs ie Monitoring and Protective equipment costs. The basis for these costings is given below. This is followed by estimates of compliance costs for each separate business sector in turn.
Monitoring
32. Monitoring of phenol would be required at sites where the risk assessment suggests that there may be a problem. The risk assessment would be based on previous monitoring results, if available, or results from similar sites. Once a MEL is set, it is possible that some sites would require an initial survey. This survey and the rest of the risk assessment will indicate what sort of further routine actions are needed. In many cases the action taken may mean that no further action is required unless conditions change significantly.
33. For phenol monitoring we can calculate some typical costs. At the lowest level the costs of buying and using a set of appropriate indicator tubes to check that measurable phenol is present will be around £100. At the highest level, a day's time for a consultant is estimated to cost between £500 and £600. A day's time for a technician is estimated to cost between £200 and £300 and the cost of a phenol analysis around £25.
Protective equipment
34. The cost of an RPE programme has been calculated by HSE in a document published in 1996 (McAlinden JJ, Costing a Respiratory protective Equipment (RPE) Programme, Specialist Inspector Report Number 50), based on 1994 prices. It gives the total cost of using and maintaining various sorts of RPE. These figures are used to estimate the RPE control costs. For a single-use disposable filtering face piece respirator, assuming only one face piece is used per shift, the annual cost of replacement would be between £288 and £840. The training is assumed to take 2 hours annually and brings the total costs to between £300 and £850 per person annually, in 1999 prices.
35. The common cost for a MEL set at either 2 ppm or 3 ppm (8-hour TWA) is as follows:
Monitoring
36. At about twenty sites (producers of phenol products, phenolic resins and sites of import from abroad) there will be a need for an initial monitoring of phenol. This will be a one-off cost of £600 (a day's consultant time) plus 10 x £25 (10 samples) for a unit total of £850. Total costs for all sites will therefore be 20 x £850 = £17,000.
37. It is likely that about two sites annually will need to re-monitor because of possible excursions close to the new limit during tanker delivery to site. This estimate is based on the possibility that 10% of sites may encounter problems. Annual costs will therefore be around £1700
RPE
38. RPE is routine for all of the procedures during loading/unloading so there will be no extra RPE costs. We believe that there will be no significant cost differences between a MEL of 2 ppm and 3 ppm (as an 8-hour TWA).
Total costs
39. Overall costs for a MEL set at either 2 ppm or 3 ppm will therefore be an initial cost of £17,000 and annual costs thereafter of £1700.
40. The common cost for a MEL set at either 2 ppm or 3 ppm (8-hour TWA) is as follows:
Monitoring
41. At about fifteen sites, there will be a need for an initial monitoring. This cost will be £1000 (two days consultation) plus £400 (two days technician time) and analysis costs of 20 x £25 (£500) making a total of £1,900. The total initial costs for all sites will therefore be £1,900 x 15 = £28,500.
42. Some sites will need to re-evaluate from time to time. Assuming that 20% of sites re-monitor annually for a MEL set at 3 ppm and 30% of sites re-monitor for a MEL set at 2 ppm, the annual costs will be £5,700 and £8,550 respectively.
RPE
43. RPE is used for emergency usage and for maintenance tasks at these sites. We believe that there will be no extra costs as a result of a MEL set at either 2 ppm or 3 ppm.
Total costs
44. Overall costs for a MEL set at 2 ppm will be an initial cost of £28,500 and annual costs of £8,550
45. Overall costs for a MEL set at 3 ppm will be an initial cost of £28,500 and annual costs of £5,700.
46. The common cost for a MEL set at either 2 ppm or 3 ppm (8-hour TWA) is as follows:
Monitoring
47. There are a restricted number of hangars available for this procedure and we estimate that overall twenty sites will be affected. Four of these sites are large and the remainder small, so the initial monitoring costs are estimated at:
48. For large sites, the cost will equal 4 x £500 (consultant or in-house expert) plus 4 x £200 (technician time) plus 4 x £500 ( 20 samples at £25 each) for a total of £4,800.
49. For small sites, the cost will equal 16 x £200 (technician time) plus 16 x £100 ( 4 samples at £25 each) for a total of £4,800
50. Total initial monitoring costs are therefore estimated at £9,600.
51. There may be differences between a MEL set at 2 ppm and one set at 3 ppm. Our data from NEDB shows that during the period 1987 to 1995, of 22 personal samples measured, 4 were above 2 ppm. More recent data (1999) showed that one personal sample out of six was above 2 ppm, but below 3 ppm. It was, however, reported that the ventilation system was not working correctly on the day in question.
52. Assuming that the monitoring will need to be repeated at one site in six if a MEL is set at 2 ppm, but at no sites if a MEL is set at 3 ppm. then the extra annual costs for a MEL set at 2 ppm will be one sixth of £9600, which is £1600.
RPE
53. RPE is routine during these procedures and it is unlikely that extra RPE will be needed.
Other costs
54. Job rotation is possibly unlikely to be feasible as all tasks will involve some degree of exposure once the paint stripper is applied. Specialised hangars can cost up to £20 million because of the sheer size of the buildings and are unlikely to be considered.
Total costs
55. Overall costs for a MEL set at 2 ppm will be an initial cost of £9,600 and annual costs of £1,600
56. Overall costs for a MEL set at 3 ppm will be an initial cost of £9,600 and annual costs of zero
57. The common cost for a MEL set at either 2 ppm or 3 ppm (8-hour TWA) is as follows:
Monitoring
58. There are a large number of sites using phenolic resins and it is difficult to realistically estimate the number of sites that will need to undertake monitoring. We assume that the monitoring will initially consist of indicator tube measurements and will be backed up by sampler measurements if required. We have only limited exposure information in this sector, but believe that a MEL set at either 2 ppm or 3 ppm will require little if any extra monitoring. if a MEL was to be set at 2 ppm, it is possible that a small proportion of sites will need to monitor initially.
59. Assuming that one hundred sites will need to spend £100 on monitoring (indicator tubes) then the total initial cost will be £10,000. This figure is speculative but gives an indication of the potential cost. As a result of the initial monitoring we assume that 10% will continue to monitor. This gives an annual cost of £1,000
RPE
60. We believe that it is unlikely that any extra RPE will be required at these sites.
Total costs
61. Overall costs for a MEL set at 2 ppm will be an initial cost of £10,000 and annual costs of £1,000
62. Overall costs for a MEL set at 3 ppm will be an initial cost of zero and annual costs of zero
62. The common cost for a MEL set at either 2 ppm or 3 ppm (8-hour TWA) is as follows:
Monitoring
63. Many sites will need to monitor initially whether the MEL is set at 2 ppm or 3 ppm. Based on our available data (NEDB and industry supplied data) very few personal samples are above 2 ppm averaged over 8 hours. Discussions with the industry trade associations indicate a belief that there is the potential for phenol exposures to rise to between 1 ppm and 2 ppm. This is close enough to one of the MELs of 2 ppm for some parts of the industry to initiate a monitoring scheme as a matter of course. Although this will incur a cost to those companies we can only calculate a cost if it is necessary to comply with the legislation.
64. There are about 900 foundries in the UK and about 50% of them use phenol, although the largest may not be included. We have assumed a figure of 200 small sites and 250 larger sites.
65. Initial monitoring cost will be as follows: approximately 100 of the small sites noted above will need to monitor (£100 for indicator tubes) leading to a cost of £10,000. 125 of the larger sites will need to monitor (£200 for one technician day and 10 samples at £25 each) for a total cost of 125 x £450 = £56250. Thus, the total initial cost of monitoring will be £66,250. We believe that only 10 of these sites will need to monitor annually if a MEL is set at 2 ppm (8 -hour TWA) leading to annual costs of £5625. For a MEL set at 3 ppm, we believe that there will be no annual monitoring costs.
RPE
66. It is unlikely much extra RPE will be used as a consequence of the MEL being set. In larger firms job rotation minimises exposure and in many cases, the problems of heat and access will mitigate against it. However there is scope for the use of ventilated helmets in some small firms on some specific occasions where job rotation is not possible. We have assumed that the costs will be based on a two year life with four replacement visors. The annual replacement cost will be between £256 and £1067.
67. Of the 300 smaller companies we believe that 10% of the 1500 workforce may need to use this type of equipment at times if the MEL is set at 2 ppm rather than 3 ppm. This will produce an annual cost of between 150 x £256 and 150 x £1067 = £38,400 and £160,050.
Total costs
68. Overall costs for a MEL set at 2 ppm will be an initial cost of between £104,650 and £226,300, and annual costs of between £44,025 and £165,675
69. Overall costs for a MEL set at 3 ppm will be an initial cost of £66,250 and annual costs of zero
70. The site costs in the previous section can be used as a reasonable approximation of the cost implications for a typical business in each sector.
MEL set at 2 ppm
71. Total initial costs are equivalent to between £169,750 and £291,400 and recurring annual costs sum to between £56,875 and £178,525. Net present costs over the 10-year appraisal period are in the range of £605,928 and £1,622,932.
MEL set at 3 ppm
72. Total initial costs are equivalent to £121,000, recurring annual costs sum to £7,400 and net present costs over the appraisal period sum to £183,000.
Table 3. Summary of total net present costs per sector (10 year appraisal period)
| Task | predicted TWA over 8 hour reference period (ppm) | Predicted TWA over 15 min reference period (ppm) |
|---|---|---|
| Phenol distribution | - | 0.7 - 6 |
| Chemical intermediate | <0.1 - 0.25 | <0.1 - 0.5 |
| Resin production | <0.1 - 0.3 | 0.5 - 5 |
| Production of friction material for brake pads | 0.0025 - 0.25 | 0.0025 - 0.25 |
73. HSE's administrative, secretarial, inspectorial and scientific staff have been used for a variety of purposes. The total cost is difficult to quantify.
74. Staff from the foundry and tank storage trade associations have spent time and energy in helping HSE in the reviewing of data and in informing their members of the progress of this review and RIA. The total cost is difficult to quantify.
75. The vast majority of the societal cost is borne by industry. This is detailed above.
76. For small foundries, there is less scope for job rotation that reduces exposure to phenol over eight hour periods. There is a possibility that some may move away from phenolic resins to alternative systems which are of a comparable cost.
77. It is believed that there will be no environmental impact of setting a MEL at either 2 ppm or 3 ppm.
78. There will be a small cost to industry associated with compliance to a MEL for phenol set at either 2 ppm or 3 ppm. The total cost of a MEL set at 2 ppm is expected to be in the range of £600,000 and £1,620,000 in present values over a ten year appraisal period. The total cost of a MEL set at 3 ppm is expected to be approximately £183,000 over the same appraisal period.
79. The benefits are subject to substantial uncertainties. It has not been possible to quantify benefits as there is no conclusive evidence regarding dose and effects.
80. However, since the uncertainty lies mainly in the number of employees who will benefit from the MEL, it is useful to consider what the costs per worker exposed are from setting this MEL, and how these costs compare with past MELs. The table below shows the cost to employers per worker exposed (rounded figures) of approved MELs for other genotoxic substances.
Table 4: Cost of exposure per worker in several recent MELs
| Substance |
Cost per worker exposed (£, 1999/2000 prices) |
|---|---|
| Dimethyl sulfate and diethyl sulphate | 410-550 |
| Hydrazine | 390-1,330 |
| Vanadium pentoxide | |
| MEL 0.5 mg.m-3 Engineering control strategy | 390-1,480 |
| RPE control strategy | 440-1,390 |
| MEL 0.1 mg.m-3 Engineering control strategy | 430-1,590 |
| RPE control strategy | 680-1,800 |
| MEL 0.05 mg.m-3 Engineering control strategy | 550-1,830 |
| RPE control strategy | 1130-2,670 |
| Phenol | |
| MEL (2 ppm) | 13.54 - 15.47 |
| MEL (3 ppm) | 2.48- 2.84 |
81. Table 4 shows that if employers follow the suggested MELs for phenol, the cost per employee exposed is likely to be much lower than the costs per employee exposed when a MEL was set for other genotoxic substances. In other words the cost per exposed worker for either of the MELs considered for phenol is lower than that which was thought acceptable for past MELs which were approved. This is also true if the cost is calculated per worker exposed at a level above 2 ppm, which results in a range of £171 - £195.
82. On the basis of the above figures it is not possible to compare benefits to costs. However, the cost per worker exposed can be used as an indicator of likely benefits. In the absence of data on predicted cases that will be prevented, the cost per worker exposed figures provide justification for approving this MEL, particularly considering the relatively small cost levied on industry.
83. Uncertainties in the assumptions made on costs are reflected in the use of range rather than point estimates.
84. The benefits are subject to substantial uncertainties. Because there is no information on dose-effect it is not possible to make a direct estimate of benefits and an alternative approach has been adopted.
85. The MEL will be enforced at workplaces by HSE. Assigning a MEL will require an increase in the emphasis inspectors attach to phenol exposure. This will result in a slightly increased workload for inspectors during inspection and any resulting enforcement action. The MEL will be revised if significant new scientific information becomes available, which places doubt on the current assessment of the health risks.
Howard Jackson,
HDC
13 June 2000