Styrene, health effects

Effects of styrene on human health depend on concentration, length of exposure, and individual genetics. Styrene vapor irritates the eyes, the nose, and the throat and can adversely affect the central nervous system. Health effects associated with breathing low concentrations of styrene over extended periods in the workplace include alterations in vision and hearing loss and increased reaction times. The Environmental Protection Agency has classified styrene as a potential human carcinogen. 

Benzene is one of the major chemicals produced by the petroleum industry. More than 1.6 billion gallons are produced each year by cracking and reforming various petroleum fractions. Most of this is used in the production of styrene, which is then polymerized to polystyrene. Other arenes that are made in large amounts include toluene (830 million gallons), cumene, o-xylene, and p-xylene. At one time, benzene was an important solvent in the organic laboratory. Recently, however, its use has been phased out because of its potential adverse health effects. Long exposure to benzene has been shown to lead to bone marrow depression and leukemia. 

Use and exposure Styrene is a colorless liquid with a sweet smell. Styrene is primarily a synthetic chemical used extensively in the manufacture of plastics, rubber, and resins. It is also used as an intermediate in the synthesis of materials used for ion exchange resins and to produce copolymers. Toxicity and health effects Acute exposure to styrene causes respiratory effects, such as mucous membrane irritation, eye irritation, and gastrointestinal effects. Styrene causes subjective complaints of headache, fatigue, dizziness, confusion, drowsiness, malaise, difficulty in concentrating, and a feeling of intoxication. Chronic exposure to styrene affects CNS depression and dysfunction, hearing loss, and peripheral neuropathy. - ... 

Kolstad HA, Ebbehpj N, Bonde JP, Lynge E, Albin M. Health effects following occupational styrene exposure in the reinforced plastics industry. Ugeskr Laeger 2012 174 (5) 267-270. 

Acute and chronic health effects are effects on the nervous system. Chronic exposiues may also result in liver damage. The presence of styrene leads to suspicion of cancer. EPA analysis method numbers are 502.2 and 524.2. 

SAN resins themselves appear to pose few health problems in that they have been approved by the EDA for beverage botde use (149). The main concern is that of toxic residuals, eg, acrylonitrile, styrene, or other polymerization components such as emulsifiers, stabilizers, or solvents. Each component must be treated individually for toxic effects and safe exposure level. 

Carlson, G.P. (1997) Effects of inducers and inhibitors on the microsomal metabolism of styrene to styrene oxide in mice. J. Toxicol, environ. Health, 51, 477-488... 

Anderson, D., Edwards, A.J. Brinkworth, M.H. (1993) Male-mediated F, effects in mice exposed to 1,3-butadiene. In Sorsa, M., Peltonen, K., Vainio, H. Hemminki, K., eds, Butadiene and Styrene Assessment of Health Hazards (I ARC Scientific Publications No. 127), Lyon, lARC, pp. 171-181... 

Occupational exposure to 2-butoxyetlianol usually involves co-exposure to other solvents and chemicals. In several NIOSH Health Hazard Evaluations, effects reported by workers included eye, nose, and throat irritation coughing runny nose headache dizziness lightheadedness and nausea. Since personal breathing zone and workplace air samples analyzed for solvents and other chemicals (such as toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, styrene) along with 2-butoxyethanoI indicated that exposure levels for each chemical were below the NIOSH, ACGIH, and OSHA criteria, NIOSH concluded that the effects were probably due to the additive combination of the solvents. 

Bergamaschi E, Smargiassi A, Mutti A, et al Peripheral markers of catecholaminergic dysfunction and symptoms of neurotoxicity among styrene-exposed workers. Int Arch Occup Environ Health 69 209-214,1997 Challenor J, Wright D Aggression in boat builders a search for altered mood states in boat builders exposed to styrene. Occup Med (Lond) 50 185-192, 2000 Cherry N, Rodgers B, Venables H, et al Acute behavioural effects of styrene exposure a further analysis. British Journal of Industrial Medicine 38 346-350, 1981 Cherry N, Hutchins H, Pace T, et al Neurohehavioural effects of repeated occupational exposure to toluene and paint solvents. British Journal of Industrial Medicine 42 291-300, 1985... 

Mutti A, Mazzucchi A, Frigeri G, et al Neuropsychological investigation on styrene exposed workers, in Neurobehavioral Methods in Occupational Health. Edited by Gilioli R, Cassitto MG, Foa V. Oxford, UK, Pergamon, 1983, pp 271-281 Mutti A, Mazzucchi A, Rustichelli P, et al Exposure-effect and exposure-response relationships between occupational exposure to styrene and neuropsychological functions. Am J Ind Med 5 275-286,1984... 

Rahovsky J, Fowles J, Hill MD, et al A health risk benchmark for the neurologic effects of styrene comparison with NAEL/LOAEL approach. Risk Anal 21 117-126, 2001... 

The styrene fumes to which a person might be exposed are mild irritants to the skin, eyes, and respiratory tract. They may cause inflammation of the skin, eyes, nose, and throat. In larger amounts, they may adversely affect the nervous system causing nausea, tiredness, muscle weakness, depression, and concentration problems. Adequate studies on the carcinogenic properties of styrene have not been conducted, but the International Agency for Research on Cancer has called styrene a possible carcinogen. There are also no studies on the possible reproductive effects of exposure to styrene. In any case, the individuals most at risk for the health hazards of styrene are people who come into contact with the chemical in the workplace. 

Impact Modifiers Impact modifiers are either systems with spherical elastomer particles in a rigid polymer matrix or they are systems with a honeycomb, network type of dispersed elastomeric phase. For the spherical elastomeric particles, examples are acrylonitrile butadiene styrene (ABS), methacrylate-butadiene-styrene (MBS) and acrylics. These systems are either graft copolymers of methyl methacrylate-butyl acrylate-styrene or methyl methacrylate-ethylhexyl acrylate-styrene. For the honeycomb, network type of dispersed elastomeric phase ethylene vinyl acetate (EVA) and chlorinated polyethylene (CPE) or directly dispersed rubber are examples. Both of these two impact modifiers exist in the polymeric form, hence they can hardly migrate and evaporate because of their size. As a result, they pose almost no problems to health. For PVC window frame production, usually the first type (and acrylic impact modifiers) are used while MBS modifiers are found to be very effective in plasticised as well as in rigid PVC. CPE is mainly used in PVC for products like sheet, pipe, gutters and sidings. 

No harmful effects on health have been observed that could have been caused by processing Terblend S under normal conditions of industrial practice in well-ventilated workplace. Under such conditions concentrations of styrene, n-butyl acrylate, and aciylonitrile are well below permitted concentrations. 

Control limits are based on Regulations, Approved Codes of Practice, European Community directives, or Health and Safety Commission instructions, and are limits which should not be exceeded. Failure to comply with a control limit may result in enforcement action by a Health and Safety Executive Inspector. With some controlled substances (i.e. those with no minimum threshold below which adverse effects do not occur, or where short exposure to high concentrations cause injury) exposures may need to be reduced to the lowest levels justifiable on a cost/risk basis. The present strategy behind the application of control limits for exposure to relatively few substances, some of which are not highly toxic, is based on the recognition that these substances are very commonly used at work. Until a few years ago, a great many were used without any real control of exposure (e.g. asbestos, vinyl chloride and lead compounds). Some, such as methylene chloride, formaldehyde and styrene, have been shown more recently to be potentially very harmful, in both the short and the long term, at levels of exposure just above the limits set, and they are included because of their widespread use at work. 

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