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- Methodology for assessing occupational exposure
- Formaldehyde manufacture
Occupational Exposure
An evaluation of available information on Australian use scenarios indicates that workers are potentially exposed to formaldehyde by both inhalation and skin contact. Ingestion is unlikely to be a route of exposure in the occupational environment. Exposure to formaldehyde may result from inhalation of vapour as formaldehyde presents mainly as a gas in the occupational environment. Heating or agitation of formaldehyde products may lead to an increased generation of vapour. Another source of formaldehyde vapour at workplaces is off-gassing from formaldehyde resins that are used widely in a number of industries, predominantly, the wood panel industry. Additionally, formaldehyde can be released as a thermal degradation product during processing of some materials under heat, such as plastics. Inhalation of aerosol droplets from accidental releases or some application modes, such as spraying or brushing, is also possible. Formaldehyde containing particles can be inhaled when paraformaldehyde or formaldehyde resin powder is being used in the workplace. Formaldehyde resins can also be attached to carriers, such as wood dust, to be inhaled. Dermal exposure may occur from spills or splashes of formaldehyde in solutions and exposure of the skin to aerosol droplets. No information was available on the potential dermal absorption of formaldehyde fumes. Occupational exposure to formaldehyde is discussed for manufacture, importation and transportation, formulation and repackaging, and use of formaldehyde products in the following sections. Published data for atmospheric monitoring of formaldehyde levels in workplaces were reviewed by IARC (1995), but the majority of them were conducted before 1990. A literature search for post-1990 monitoring data was conducted and the results are summarised in the following sections. Recent Australian air monitoring data at workplaces were collected during this assessment and are also summarised.
Together with the use profiles described in Chapter 7, information on occupational exposure and control measures obtained from industry were evaluated. A reasonable amount of air monitoring data was received during the assessment, especially for formaldehyde and formaldehyde resin manufacture, and use of some formaldehyde resin products (mainly wood products). Due to the limited amount of monitoring data for other use scenarios, all data are presented in Tables 15.1 to 15.9 with information on number of samples, exposure duration, sampling and analytical methods, results, and relevant comments. However, it is noted that there are limitations for some data presented, for example, the reported single sample results are likely to involve a large coefficient of variation. Due to lack of measured exposure data in some use scenarios, such as film processing, the EASE (Estimation and Assessment of Substance Exposure) model (version 2.0 for Windows), developed by the United Kingdom Health and Safety Executive (UK HSE, 2000) was used to estimate occupational exposure. The detail on this model and modelling results are summarised in Appendix 8. Formaldehyde manufacture involves a series of continuous and enclosed processes. The four manufacturers reported a total of approximately 120 employees working in processes with potential exposure to formaldehyde, such as production and maintenance, quality control, laboratory and storage. This figure includes workers in the resin manufacturing plants as workers have dual roles in formaldehyde and resin production at most sites. The potential for exposure to formaldehyde during manufacture is limited due to the fully enclosed nature of the processes. However, workers’ exposure could result from truck loading and/or drum filling and from situations where there is a need to break open or enter the enclosed system, such as sample collecting and testing, equipment cleaning and maintenance. During formaldehyde manufacture, samples are manually taken from formaldehyde plants or storage tanks through a tap at the bottom of the formaldehyde absorber tower/storage tank using a jar, about three to four times per shift. The storage tanks are located outside buildings at all formaldehyde manufacturing sites. Analysis of the samples is done for parameters, such as pH and presence of by-products in a quality control laboratory under a fume hood, and usually takes less than 5 minutes. Equipment maintenance is conducted regularly during formaldehyde manufacture. It was reported that typically the reaction chamber and the absorber tower are cleaned only occasionally. The frequency of the catalyst replacement varies and ranges from once in one to three years depending on the manufacturing efficiency. Specially trained personnel conduct the maintenance tasks while the manufacturing operation is shut down. Higher formaldehyde levels may occur during maintenance tasks, particularly in confined spaces, but are generally short- term and limited to work situations that require the use of respiratory protective equipment. Exposure during storage is limited as formaldehyde storage tanks and pipes are of stainless steel with insulation and heat tracing where required. Storage tanks are above ground, bunded and closed except for vent pipes. The potential for exposure during transfers using piping systems is likely to be low, but could be high during manual drum filling. It was reported that local exhaust ventilation is fitted at tank sampling and drum filling points at two sites. Laboratories are equipped with fume hoods. Operators wear overalls, helmet, gloves, safety glasses and boots during normal duties at production plants. Respiratory protection equipment is available and used where exposures are likely to be high, such as reaction chamber/absorber tower cleaning (confined spaces) and dealing with major spills. Directory: data -> assets -> word doc -> 0006 word doc -> Commonwealth of Australia 2002 word doc -> Commonwealth of Australia 2000 word doc -> Priority Existing Chemical word doc -> Rail safety news issue 6 – October 2011 word doc -> Review of Multiple Chemical Sensitivity: Identifying 0006 -> Board Endorsed October 2009 amended 13-09-11 with extra units 0006 -> Rt Hon Andrew Lansley cbe mp secretary of State for Health 0006 -> Environmental Approvals Application Form Use this form Download 5.77 Mb. Share with your friends:
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