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- Resin manufacture
- Measured exposure data
- Formulation of formaldehyde products other than resins
Formulation and repackagingNo information was available on the total number of workers handling formaldehyde during formulation and repackaging. At the majority of workplaces surveyed, one to three operators are involved in each stage of the batch formulation process (weighing, loading, mixing and equipment cleaning). The number of workers involved in the decanting process varies depending on batch sizes. Usually one to two operators are involved in repackaging.
Eleven formaldehyde resin manufacturers provided information, however, it is likely that there are more in Australia. The likelihood of exposure is low for most workers during resin manufacture as the reactions involving formaldehyde occur in enclosed systems. Also the majority of production sites have enclosed systems for transferring formalin into the reactor and resin decanting. However, operators could be exposed to formaldehyde during abnormal operations, such as mechanical failure of hoses or seals and failure to ensure all hatches and chutes are closed. Exposure could also occur during the following activities or events: sample collection and testing, truck loading and unloading, filling of drums, equipment cleaning and maintenance, opening of tanks and equipment, and spills. However, these activities either take a short period to undertake (such as sampling), or are infrequent or accidental. In addition, workers are required to wear safety glasses, gloves, overalls and safety footwear when handling formaldehyde or formaldehyde resins at all sites. Full-face air supplied respirators or breathing masks are worn during truck loading at two companies. Local exhaust ventilation and general ventilation are used for loading and packaging areas at the majority of workplaces. At large resin manufacturing sites, typically 10 to 20 samples per shift are taken manually from sample ports of the reactors and tested for viscosity and pH. Sampling takes less than 5 minutes. Small amounts of resin (as samples) are also made in the laboratory approximately 2 times per shift and take 4 to 5 hours to test each time. All laboratories have fume hoods. Local exhaust ventilation is also available in a laboratory which houses experimental resin reactors. Equipment cleaning and maintenance are conducted regularly during formaldehyde resin manufacture. The frequency of the reaction tower cleaning varies from site to site and ranges from once every 6 months to 3 years. The tasks are conducted by specially trained personnel while the manufacturing operation is shut down. The required personal protective equipment (PPE), such as air- supplied breathing apparatus for working in confined spaces, is used. The potential for inhalation and skin exposure of workers during resin manufacture is likely to be higher at worksites where manual charging of formalin from drums or paraformaldehyde prills from sealed bags, and manual drum filling of resins are undertaken. Measured exposure dataRecent personal and static air monitoring data (1998-2003) during formaldehyde resin manufacture was provided by a number of companies and is summarised in Table 15.2a and Table 15.2b, respectively. Almost all long-term personal monitoring results (except at site number 7 in Table 15.2a) were ≤0.5 ppm, with the majority of them (88 out of 95) ≤0.2 ppm. One high reading (1.96 ppm) was measured when formaldehyde vapours were released during flushing of the formaldehyde pump and opening of tanker hatches by a driver. The data from site number 7, which has the most number of samples (176), showed a similar pattern, with 76 out of 89 showing readings ≤0.5ppm , in which 63 readings were ≤0.2ppm. The company claimed that exposures in the plant operating environment and laboratory were typically less than 0.1 ppm for the duration of 12 hour (operators) and 8 hour (laboratory staff) shifts. Similarly, most of the short-term measurement results were less than 0.5 ppm (66 out of 87). The long-term static data showed that 46 out of 50 sample results are ≤0.2 ppm (Table 15.2b). The majority of short-term static measurements were also ≤0.2 ppm, with 11 out of 74 samples in the result band of > 0.5 ppm to 2 ppm. Weekly static monitoring (100 samples in total between year 2001 and April 2003) was undertaken at site number 9 and most of readings were < 0.2 ppm. The company reported that the highest routine exposures are 0.5 ppm to 1 ppm during sampling and testing. Information from industry indicates that where high exposures are recorded, an investigation into likely causes is initiated and corrective actions are carried out. For example, the results measured near the scrubber extraction at site number 8 (with limited details on methodology) were high (4 - 4.3 ppm), but were reduced to lower than 2 ppm after the ventilation system was improved (Table 15.2b). No recent overseas air monitoring data on formaldehyde levels during resin manufacture were identified. Earlier data reported mean concentrations of formaldehyde during resin manufacture vary from < 1 ppm to 14 ppm, with majority < 3 ppm (IARC, 1995). Therefore, the current levels of formaldehyde in Australia are much lower compared with overseas data of two decades ago.
Forty-eight formulators of formaldehyde products other than resins provided information, however, it is likely that there are more formulators in Australia. There are a variety of formulation processes, ranging from open tanks to enclosed systems, using formalin or products containing formaldehyde as raw materials (see Table 7.4). Operators are likely to be exposed by skin contact during manual charging of mixing vessels, mixing and inspection, filling of product containers and equipment cleaning. There is also a potential for inhalation exposure, especially during charging of formalin into open vessels, heated blending processes and high-speed mechanical stirring in open tanks. Sampling is usually conducted at the end of mixing and samples are taken through a sampling tap at the bottom of the mixing vessel. Equipment is cleaned between different products by hosing with pressured water or using cleaning solvents. 152 Priority Existing Chemical Assessment Report No. 28 Table 15.2a: Summary of personal monitoring data during formaldehyde resin manufacture Site* Activity No. of samples Duration Test method Results# (ppm) Comment Year 1 resin operators/QC chemist maintenance/R&D chemist/laboratory staff/truck loading worker 32 12 h 3M method 3721 monitor 25 ≤0.1 5 >0.1-0.2 1 >0.2-0.3 1 >0.3-0.5 25 8 h 3M method 3721 monitor 17 ≤0.1 8 >0.1-0.2 1998-2001
2 kettle charging/ changing bag & filters/drum filling 14 19-210 min Pre-calibrated Dupont Sampling pump 11 ≤0.1 3 >0.1-0.2 1998-2001 kettle charging 1 1 h Method MA-1159 0.07 (12h TWA) Method MA-1159 is an internal method by Leeder Consulting Pty Ltd. 2003
3 NR 1 6 h AMCOSH 50056 <0.01 2001
12 35-700 min. NIOSH 2016 6 ≤0.1 3 >0.1-0.2 3 >0.5-2
89 8-12 h passive dosimeter badges analysed by LC 46 ≤0.1 17 >0.1-0.2 7 >0.2-0.3 6 >0.3-0.5 13 >0.5-2 3 readings in the band >0.5-2ppm were due to plant breakdown. 2 readings where workers worn full-face canister. 2000 - 2002
87 2-15 min. combination of passive 33 ≤0.1
One reading of 3.6 ppm was due to opening formaldehyde dosimeter badges, Drager tubes 11 >0.1-0.2 storage oven. For other 4 readings of >2ppm workers worn and a direct read, hand held 5 >0.2-0.3 respirators.
electronic formaldehyde device 17 >0.3-0.5 16 >0.5-2 5 >2
8 Mixing/pack off 5 300-400 min. Dosi tube/impinger 3 ≤0.1 2 >0.2-0.3 1999-2002
NR, not reported; LC, liquid chromatography; AMCOSH, Advice Measurement and Control in Occupational Safety and Health; QC, quality control; R&D, research and development; NIOSH, National Institute for Occupational Safety and Health; TWA, time-weighted average. *Site 4 does not have personal monitoring data. # The results are presented as the number of samples in a series of result bands. Formaldehyde 153
Table 15.2b: Summary of static monitoring data during formaldehyde resin manufacture
6 >0.5-2
3 >0.5-2 NR, not reported; AMCOSH, Advice Measurement and Control in Occupational Safety and Health; NIOSH, National Institute for Occupational Safety and Health; AS, Australian Standard. *Sites 3 and 7 do not have static monitoring data. # The results are presented as the number of samples in a series of result bands.
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