Original article. Hazardous atmosphere in the underground pits of rice mills in Thailand

Open access

Abstract

Background: Asphyxiation is the most dangerous hazard in confined spaces. In Thailand, several large rice mills have underground pits in order to transport moist paddy to baking machines. Prolonged unbaked paddy piles can produce several gases that can displace oxygen inside the pits.

Objective: This study describes concentrations of hazardous gases and oxygen content inside the underground pits of rice mills in Thailand.

Methods: At six randomly selected large rice mills in this study, fresh paddy piles were divided into four groups, based on moisture content (<14%, 15-20%, 21-30%, and >30% wet basis (w.b.)). Gas measurement was conducted with direct reading instruments including infrared spectrophotometer (Miran 1BX for CO2, N2O) and toxic gas detector (QRAE plus for CO, NO2, % O2 and flammable gas) at three different depth levels (top, middle, bottom) inside the pits.

Results: The concentrations of CO2, CO, N2O, NO2, and % O2 were in the ranges of 1.7-5438 ppm, 0-61 ppm, 0-4.9 ppm, 0-0.8 ppm, and 19.9-21.6%, respectively whereas concentrations of flammable gas (% lower explosive limit; [%LEL]) were not detected. The highest concentrations of gases were at the middle depth pit level, inside the paddy piles with the highest moisture contents (>30% w.b.). The detected concentrations of gases were higher than limit values based on time-weighted average but below limits immediately dangerous to life.

Conclusion: Although oxygen-deficient atmosphere was not detected under the working conditions of the survey. The findings demonstrated that concentrations of hazardous gases were dependent on both storage time and the moisture content of paddy piles. Measures should be developed to ensure that entry into these pits strictly complies with safety laws

1. National Institute for Occupational Safety and Health (NIOSH). NIOSH FACE reports: confined space [Internet] 2011 [cited 2011 Mar 16]. Available from: http://www2a.cdc.gov/NIOSH-FACE/state.asp?state=ALL&Incident_Year=ALL&Category2=0004& Submit=Submit

2. Thepaksorn P, Daniell EW, Padungtod C, Keifer CM. Occupational accidents and injuries in Thailand. Int JOccupMed Environ Health. 2007; 3:290-4.

3. SiamSafety.com. Statistic of accidents in confined space[Internet] 2011 [cited 2010 Jan 20]. Available from: http://www.siamsafety.com/index.php?page=forums/view&type_forum=2&ps_session=d5397561380c03279bd05f959748310f&message_id=62345

4. Khon Kaen Hospital, Khon Kaen Province, Thailand. Lesson’s from the investigationan outbreak of casualties in rice mill factory KhonKaen Province [Internet] 2005 [cited 2006 Feb 16]. Available from: http://203.157.88.5/nurse/research/19.htm

5. Big picture agriculture. Rice export statistics [Internet] 2010[cited 2011 Jan10]. Available from: http://bigpictureagriculture.blogspot.com/2010/11/riceexport-statistics.html

6. Department of Industry, Ministry of Industry, Thailand. The listsof registered rice mills [Internet] 2006[cited 2006 Nov 18]. Available from: http://www.diw.go.th/diw_web/html/versionthai/laws/lawmenu2.asp

7. Tantivirasut P. Traditional and modern rice mill. Kasikorn J. 1998; 6:551-9 [in Thai].

8. Soponraonnarit S, Amatachaya P, Prachayawarakorn S, NathakaranakuleA, Inchan S.Field trial of in-store paddy drying and storage. The Kasetsart Journal (Social science). 1997; 1:86-100.

9. Tumambing JA. Current drying practices and needs in ASEAN. Proceedings of aninternational workshop held at Kuala Lumpur [Internet] 1988[cited 2009 Jan 30]. Available from: http://aciar.gov.au/files/node/312/bulk_handling_and_storage_of_grain_in_the_humid_tr_33881.pdf

10. Wiset L, Srzednicki G, Driscoll RH, Nimmuntavin C, Siwapornrak P. Effect of high temperature drying on rice quality [Internet] 2001 [cited 2009 Mar 25].Available from: http://www.cigrjournal.org/index.php/Ejounral/article/view/191/185

11. Sage V Foods. Storage and milling of rice [Internet] 2008 [cited 2008 Jan 20]. Available from: http://www.sagevfoods.com/MainPages/Rice101/Milling.htm

12. Sund JM, Niedermeier RP, Burris RH. Watch out for silo gas [Internet] 2002 [cited 2009 Dec 10]. Available from: http://nasdonline.org/document/901/d000741/watch-out-for-silage-gas.html

13. Conrad R, Smith KA. Soil microbial processes and the cycling of atmospheric trace gases. Philosophical Transactions: Physical Sciences and Engineering 1995; 351:219-30.

14. Conrad R.Soil micro-organism as controllers of atmospheric trace gases (H2, CO,CH4, OCS, N2O, and NO). Microbiol Rev. 1996; 60:609-40.

15. Stafford D, Hawkes D, Horton R. Methane production from waste organic matter. FL USA: CRC Press; 1980.

16. Khali MAK, Rasmussen RA. Atmospheric methane, ice ages, and population: a graphical review of methane concentrations over the past 160,000 years. Antarctic Journal of the United States.1989; 13:177-8.

17. National Institute for Occupational Safety and Health (NIOSH), Fatality and Assessment and Control Evaluation (FACE) Program. Farmer asphyxiated due to lack of oxygen after entering an oxygen limiting silo 3 days after filling [Internet] 2002 [cited 2006Feb 23]. Available from: http://www.cdc.gov/niosh/face/stateface/mi/02mi143.html

18. Occupational Safety and Health Administration (OSHA). Permit-required confined spaces OSHA regulations (Standards-29 CFR)-1910.146 [Internet] 1993 [cited 2006 Dec 12]. Available from: http://www.osha.gov/pls/oshaweb/owadisp.Showdocumentp_table=standards&p_id=9797

19. National Institute of Occupational Safety and Health (NIOSH). Criteria for a recommended standard: working in confined spaces [Internet] 1979 [cited 2009 Jan 24]. Available from: http://www.cdc.gov/niosh/pdfs/80-106b.pdf

20. Center for Disease Control and Prevention, U.S. Department of Health and Human Services.NIOSH Pocket Guide to Chemical Hazards. Neenah: Wisconsin USA. J.J. Keller and Associate, Inc; 1997.

21. Dillahunty AL, Siebenmorgen TJ, Buescher RW, Smith DE, Mauromoustakos A. Effect of moisture content and temperature on respiration rate of rice. Cereal Chemistry.2000; 5:541-3.

22. Groves JA, Ellwood PA. Gases in Forage Tower Silos. Annals of Occupational Health.1989; 4:519-35.

23. Washington State Department of Labor and Industries. Two teen workers asphyxiate in an agricultural silo: Fatality investigation report [Internet] 2008 [cited 2011 Jan 20]. Available from: http://www.lni.wa.gov/Safety/Research/Face/Files/Silo.pdf

24. Hellebrand HJ. Emission of Nitrous oxide and other trace gases during composting of grass and green waste.J AgricEngng Res. 1998; 68:365-75.

25. Kedan G, Spielholz P, Sjostrom T, Trenary B, Clark RE. An assessment of gas in oxygen-deficient hay silos and the effects of forced ventilation.J AgricSaf Health. 2007; 1:83-95.

Journal Information


IMPACT FACTOR 2017: 0.209
5-year IMPACT FACTOR: 0.243

CiteScore 2017: 0.24

SCImago Journal Rank (SJR) 2017: 0.162
Source Normalized Impact per Paper (SNIP) 2017: 0.173

Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 87 87 7
PDF Downloads 30 30 3