Sunday, 27 February 2011 06:41

Environmental and Public Health Issues

Rate this item
(0 votes)

All rubber products start out as a “rubber compound”. Rubber compounds start with a rubber polymer, either natural or one of the many synthetic polymers, fillers, plasticizers, anti-oxidants, process aids, activators, accelerators and curatives. Many of the chemical ingredients are classified as hazardous or toxic chemicals, and some may be listed as carcinogens. Handling and processing of these chemicals create both environmental and safety concerns.

Hazardous Waste

Ventilation systems and dust collectors are necessary for workers handling and weighing the rubber chemicals and for workers mixing and processing the uncured rubber compound. Personal protection equipment may also be necessary for these workers. The material collected in the dust collectors must be tested to determine whether it is a hazardous waste. It would be a hazardous waste if it is reactive, corrosive, flammable or contains chemicals that are listed hazardous as wastes.

Hazardous waste must be listed on a manifest and sent for disposal at a hazardous wastesite. Non-hazardous waste can go to local sanitary landfills or may have to go to an industrial landfill, depending on applicable environmental regulations.

Air Pollution

Some rubber products require a rubber cement application in the manufacturing process. Rubber cements are made by mixing the uncured rubber compound with a solvent. The solvents used in this process are usually classified as volatile organic compounds (VOCs). Processes that use VOCs must have some type of emission-control equipment. This equipment can be a solvent recovery system or a thermal oxidizer. A thermal oxidizer is an incineration system that destroys the VOCs by combustion and usually requires a fuel supplement such as natural gas. Without emission control equipment the VOCs can cause health concerns in the factory and in the community. If the VOCs are photochemically reactive, they will affect the ozone layer.

When rubber parts are cured and the curing vessel is opened, curing fumes rush out of the vessel and from the rubber part. These fumes will be in the form of smoke, steam or both. Curing fumes can carry unreacted chemicals, plasticizers, mould lubes and other materials out into the atmosphere. Emission controls are needed.

Ground and Water Pollution

Storage and handling of VOCs must be done with extreme caution. In past years, VOCs were stored in underground storage tanks, which in some cases resulted in leaks or spills. Leaks and/or spills around underground storage tanks generally result in soil and groundwater contamination, which triggers expensive soil and groundwater remediation. The best storage choice is above-ground tanks with good secondary containment for spill prevention.

Waste Rubber

Every manufacturing process has process and finished goods scrap. Some of the process scrap can be reprocessed in the intended product or other product processes. However, once the rubber is cured or vulcanized, it can no longer be reprocessed. All cured process and finished goods scrap becomes waste material. Disposal of scrap or waste rubber products has become a worldwide problem.

Every household and business in the world uses some type of rubber product. Most rubber products are classified as non-hazardous materials and therefore would be non-hazardous waste. However, rubber products such as tyres, hose and other tubular products create an environmental problem as related to disposal after their useful life.

Tyres and tubular products cannot be buried in a landfill because the void areas trap air, which causes the products to rise to the surface over time. Shredding the rubber products eliminates this problem; however, shredding requires special equipment and is very expensive.

Smoldering tyre fires can generate large amounts of irritating smoke that can contain a wide variety of toxic chemicals and particulates.

Incineration of Scrap Rubber

One of the options for disposing of scrap rubber products and process scrap rubber from the manufacturing processes is incineration. Incineration might initially seem to be the best solution for disposal of the numerous “worn out” rubber products that exist in the world today. Some rubber-manufacturing companies have looked at incineration as a means of disposing of scrap rubber parts as well as cured and uncured rubber-process scrap. In theory, the rubber could be burned to generate steam that could be used back in the factory.

Unfortunately, it is not that simple. The incinerator must be designed so as to handle air emissions and would most likely require scrubbers to remove such contaminants as chlorine. Chlorine emissions generally would come from burning products and scrap that contain chloroprene polymers. The scrubbers generate an acidic discharge that may have to be neutralized prior to discharge.

Almost all rubber compounds contain some type of fillers, either carbon blacks, clays, calcium carbonates or hydrated silica compounds. When these rubber compounds are burned, they generate ash equivalent to the filler loading in the rubber compound. The ash is collected either by wet scrubbers or dry scrubbers. Both methods must be analysed for heavy metals prior to disposal. Wet scrubbers most likely will produce a wastewater that contains 10 to 50 ppm zinc. This much zinc being discharged into a sewage system will create problems at the treatment plant. If this occurs, then a treatment system for the removal of zinc must be installed. This treatment system then generates a zinc-containing sludge that must be shipped out for disposal.

Dry scrubbers generate an ash that must be collected for disposal. Both wet and dry ash is difficult to handle, and disposal can be a problem since most landfills do not accept this type of waste. Both wet and dry ash can be very alkaline if the rubber compounds being burned are heavily loaded with calcium carbonate.

Finally, the amount of steam generated is not enough to supply the full amount necessary to operate a rubber-manufacturing facility. The scrap rubber supply is inconsistent, and efforts are currently underway to reduce scrap, which would reduce the fuel supply. The maintenance cost of an incinerator designed to burn rubber scrap and rubber products is also very high.

When all of these costs are taken into consideration, incineration of scrap rubber may be the least cost-effective method of disposal.


Perhaps the best solution to environmental and health concerns associated with manufacturing rubber products would be good engineering control for producing and compounding powdered chemicals used in rubber compounds, and recycling programmes for all uncured and cured rubber process scrap and products. The powdered chemicals collected in dust-collector systems could be added back to rubber compounds with the appropriate engineering controls, which would eliminate the landfilling of these chemicals.

Controlling the environmental and health issues in the rubber industry can be done, but it will not come easy or be free. The cost associated with controlling environmental and health problems must be added back to the cost of rubber products.



Read 4042 times Last modified on Tuesday, 28 June 2011 13:27
More in this category: « Ergonomics

" DISCLAIMER: The ILO does not take responsibility for content presented on this web portal that is presented in any language other than English, which is the language used for the initial production and peer-review of original content. Certain statistics have not been updated since the production of the 4th edition of the Encyclopaedia (1998)."


Rubber Industry References

American Conference of Governmental Industrial Hygienists (ACGIH). 1995. Industrial Ventilation: A Manual of Recommended Practice, 22nd ed. Cincinnati: OH: ACGIH.

Andjelkovich, D, JD Taulbee, and MJ Symons. 1976. Mortality experience in a cohort of rubber workers, 1964–1973. J Occup Med 18:386–394.

Andjelkovich, D, H Abdelghany, RM Mathew, and S Blum. 1988. Lung cancer case-control study in a rubber manufacturing plant. Am J Ind Med 14:559–574.

Arp, EW, PH Wolf, and H Checkoway. 1983. Lymphocytic leukemia and exposures to benzene and other solvents in the rubber industry. J Occup Med 25:598–602.

Bernardinelli, L, RD Marco, and C Tinelli. 1987. Cancer mortality in an Italian rubber factory. Br J Ind Med 44:187–191.

Blum, S, EW Arp, AH Smith, and HA Tyroler. 1979. Stomach cancer among rubber workers: An epidemiologic investigation. In Dusts and Disease. Park Forest, IL: SOEH, Pathotox Publishers.

Checkoway, H, AH Smith, AJ McMichael, FS Jones, RR Monson, and HA Tyroler. 1981. A case-control study of bladder cancer in the U.S. tire industry. Br J Ind Med 38:240–246.

Checkoway, H, T Wilcosky, P Wolf, and H Tyroler. 1984. An evaluation of the associations of leukemia and rubber industry solvent exposures. Am J Ind Med 5:239–249.

Delzell, E and RR Monson. 1981a. Mortality among rubber workers. III. Cause-specific mortality 1940–1978. J Occup Med 23:677–684.

—. 1981b. Mortality among rubber workers. IV. General mortality patterns. J Occup Med 23:850–856.

Delzell, E, D Andjelkovich, and HA Tyroler. 1982. A case-control study of employment experience and lung cancer among rubber workers. Am J Ind Med 3:393–404.

Delzell, E, N Sathiakumar, M Hovinga, M Macaluso, J Julian, R Larson, P Cole, and DCF Muir. 1996. A follow-up study of synthetic rubber workers. Toxicology 113:182–189.

Fajen, J, RA Lunsford, and DR Roberts. 1993. Industrial exposure to 1,3-butadiene in monomer, polymer and end-user industries. In Butadiene and Styrene: Assessment of Health Hazards, edited by M Sorsa, K Peltonen, H Vainio and K Hemminki. Lyon: IARC Scientific Publications.

Fine, LJ and JM Peters. 1976a. Respiratory morbidity in rubber workers. I. Prevalence of respiratory symptoms and disease in curing workers. Arch Environ Health 31:5–9.

—. 1976b. Respiratory morbidity in rubber workers. II. Pulmonary function in curing workers. Arch Environ Health 31:10–14.

—. 1976c. Studies of respiratory morbidity in rubber workers. III. Respiratory morbidity in processing workers. Arch Environ Health 31:136–140.

Fine, LJ, JM Peters, WA Burgess, and LJ DiBerardinis. 1976. Studies of respiratory morbidity in rubber workers. IV. Respiratory morbidity in talc workers. Arch Environ Health 31:195–200.

Fox, AJ and PF Collier. 1976. A survey of occupational cancer in the rubber and cablemaking industries: Analysis of deaths occurring in 1972–74. Br J Ind Med 33:249–264.

Fox, AJ, DC Lindars, and R Owen. 1974. A survey of occupational cancer in the rubber and cablemaking industries: Results of a five-year analysis, 1967–71. Br J Ind Med 31:140–151.

Gamble, JF and R Spirtas. 1976. Job classification and utilization of complete work histories in occupational epidemiology. J Occup Med 18:399–404.

Goldsmith, D, AH Smith, and AJ McMichael. 1980. A case-control study of prostate cancer within a cohort of rubber and tire workers. J Occup Med 22:533–541.

Granata, KP and WS Marras. 1993. An EMG-assisted model of loads on the lumbar spine during asymmetric trunk extensions. J Biomech 26:1429–1438.

Greek, BF. 1991. Rubber demand is expected to grow after 1991. C & EN (13 May): 37-54.

Gustavsson, P, C Hogstedt, and B Holmberg. 1986. Mortality and incidence of cancer among Swedish rubber workers. Scand J Work Environ Health 12:538–544.

International Agency for Research on Cancer (IARC). 1992. 1,3-Butadiene. In IARC Monographs on the Evaluation of Carcinogenic Risks to Humans: Occupational Exposures to Mists and Vapours from Strong Inorganic Acids and Other Industrial Chemicals. Lyon: IARC.

International Institute of Synthetic Rubber Producers. 1994. Worldwide Rubber Statistics. Houston, TX: International Institute of Synthetic Rubber Producers.

Kilpikari, I. 1982. Mortality among male rubber workers in Finland. Arch Environ Health 37:295–299.

Kilpikari, I, E Pukkala, M Lehtonen, and M Hakama. 1982. Cancer incidence among Finnish rubber workers. Int Arch Occup Environ Health 51:65–71.

Lednar, WM, HA Tyroler, AJ McMichael, and CM Shy. 1977. The occupational determinants of chronic disabling pulmonary disease in rubber workers. J Occup Med 19:263–268.

Marras, WS and CM Sommerich. 1991. A three dimensional motion model of loads on the lumbar spine, Part I: Model structure. Hum Factors 33:123–137.

Marras, WS, SA Lavender, S Leurgans, S Rajulu, WG Allread, F Fathallah, and SA Ferguson. 1993. The role of dynamic three dimensional trunk motion in occupationally-related low back disorders: The effects of workplace factors, trunk position and trunk motion characteristics on injury. Spine 18:617–628.

Marras, WS, SA Lavender, S Leurgans, F Fathallah, WG Allread, SA Ferguson, and S Rajulu. 1995. Biomechanical risk factors for occupationally related low back disorder risk. Ergonomics 35:377–410.

McMichael, AJ, DA Andjelkovich, and HA Tyroler. 1976. Cancer mortality among rubber workers: An epidemiologic study. Ann NY Acad Sci 271:125–137.

McMichael, AJ, R Spirtas, and LL Kupper. 1974. An epidemiologic study of mortality within a cohort of rubber workers, 1964–72. J Occup Med 16:458–464.

McMichael, AJ, R Spirtas, LL Kupper, and JF Gamble. 1975. Solvent exposures and leukemia among rubber workers: An epidemiologic study. J Occup Med 17:234–239.

McMichael, AJ, R Spirtas, JF Gamble, and PM Tousey. 1976a. Mortality among rubber workers: Relationship to specific jobs. J Occup Med 18:178–185.

McMichael, AJ, WS Gerber, JF Gamble, and WM Lednar. 1976b. Chronic respiratory symptoms and job type within the rubber industry. J Occup Med 18:611–617.

Monson, RR and KK Nakano. 1976a. Mortality among rubber workers. I. White male union employees in Akron, Ohio. Am J Epidemiol 103:284–296.

—. 1976b. Mortality among rubber workers. II. Other employees. Am J Epidemiol 103:297–303.

Monson, RR and LJ Fine. 1978. Cancer mortality and morbidity among rubber workers. J Natl Cancer Inst 61:1047–1053.

National Fire Protection Association (NFPA). 1995. Standard for Ovens and Furnaces. NFPA 86. Quincy, MA: NFPA.

National Joint Industrial Council for the Rubber Manufacturing Industry. 1959. Running Nip Accidents. London: National Joint Industrial Council for the Rubber Manufacturing Industry.

—.1967. Safe Working of Calenders. London: National Joint Industrial Council for the Rubber Manufacturing Industry.

Negri, E, G Piolatto, E Pira, A Decarli, J Kaldor, and C LaVecchia. 1989. Cancer mortality in a northern Italian cohort of rubber workers. Br J Ind Med 46:624–628.

Norseth, T, A Anderson, and J Giltvedt. 1983. Cancer incidence in the rubber industry in Norway. Scand J Work Environ Health 9:69–71.

Nutt, A. 1976. Measurement of some potentially hazardous materials in the atmosphere of rubber factories. Environ Health Persp 17:117–123.

Parkes, HG, CA Veys, JAH Waterhouse, and A Peters. 1982. Cancer mortality in the British rubber industry. Br J Ind Med 39:209–220.

Peters, JM, RR Monson, WA Burgess, and LJ Fine. 1976. Occupational disease in the rubber industry. Environ Health Persp 17:31–34.

Solionova, LG and VB Smulevich. 1991. Mortality and cancer incidence in a cohort of rubber workers in Moscow. Scand J Work Environ Health 19:96–101.

Sorahan, R, HG Parkes, CA Veys, and JAH Waterhouse. 1986. Cancer mortality in the British rubber industry 1946–80. Br J Ind Med 43:363–373.

Sorahan, R, HG Parkes, CA Veys, JAH Waterhouse, JK Straughan, and A Nutt. 1989. Mortality in the British rubber industry 1946–85. Br J Ind Med 46:1–11.

Szeszenia-Daborowaska, N, U Wilezynska, T Kaczmarek, and W Szymezak. 1991. Cancer mortality among male workers in the Polish rubber industry. Polish Journal of Occupational Medicine and Environmental Health 4:149–157.

Van Ert, MD, EW Arp, RL Harris, MJ Symons, and TM Williams. 1980. Worker exposures to chemical agents in the manufacture of rubber tires: Solvent vapor studies. Am Ind Hyg Assoc J 41:212–219.

Wang, HW, XJ You, YH Qu, WF Wang, DA Wang, YM Long, and JA Ni. 1984. Investigation of cancer epidemiology and study of carcinogenic agents in the Shanghai rubber industry. Cancer Res 44:3101–3105.

Weiland, SK, KA Mundt, U Keil, B Kraemer, T Birk, M Person, AM Bucher, K Straif, J Schumann, and L Chambless. 1996. Cancer mortality among workers in the German rubber industry. Occup Environ Med 53:289–298.

Williams, TM, RL Harris, EW Arp, MJ Symons, and MD Van Ert. 1980. Worker exposure to chemical agents in the manufacture of rubber tires and tubes: Particulates. Am Ind Hyg Assoc J 41:204–211.

Wolf, PH, D Andjelkovich, A Smith, and H Tyroler. 1981. A case-control study of leukemia in the U.S. rubber industry. J Occup Med 23:103–108.

Zhang, ZF, SZ Yu, WX Li, and BCK Choi. 1989. Smoking, occupational exposure to rubber and lung cancer. Br J Ind Med 46:12–15.