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Vinyl Chloride Monomer (VCM)

VCM, which is the intermediate raw material for PVC, has a boiling point of - 13.9°C and a flash point of - 78°C. Caution is required upon handling since it is a dangerous substance in gaseous form. The PVC industry in Europe handles VCM with utmost care at PVC manufacturing facilities and ensures a safe working environment.

Although VCM is a dangerous substance in terms of flammability and reactivity it can be distributed and handled safely provided that appropriate precautions are observed.

Distribution is already subject to regulations within most countries in Europe. In additional, international movement by road, rail, sea and inland waterway is subject to agreements that lay down specific requirements that must be observed by all parties involved. National regulations may contain additionalrequirements.

As part of its commitment to the Responsible Care© programme of the European Chemical Industry Council (Cefic), the PVC industry has prepared additional guidelines. These cover all aspects of transport activity from loading to delivery point.

A copy of the full guidelines can be obtained from the ECVM secretariat.

The PVC industry is also endeavouring to reduce as much as possible the (already low) exposure of local populations to VCM. Guidelines for monitoring such exposure have been developed.

VCM and health effects

In 1974, cancers were reported among workers who had been employed by the PVC industry in the U.S. and VCM was found to be responsible. As a result of an epidemiological survey, a very rare type of cancer (angiosarcoma of the liver) was identified in workers who had been exposed to high concentrations of VCM for an extended period of time. Most cancer cases occurred among workers who cleaned polymerization reactors for extended periods of time.

Following this report, improvements of working environments were accelerated through the implementation of improvements in EDC/VCM manufacturing processes, of closed polymerisation reactor systems and automated cleaning of PVC polymerisation reactors. Subsequently, better process control technologies were introduced such as enhanced polymerisation conversions and recovery of un-reacted VCM from the reactor.

In the European Community, a Directive adopted in 1978 set a maximum VCM occupational exposure level of 3 ppm, on an yearly average basis and mandated monitoring of VCM concentration in the working area. The limit was later set at 3 ppm for 8 hours time weighted average. The regulation currently in force is Directive 2004/37/EC “on the protection of workers from the risk related to exposure to carcinogens or mutagens at work”. Several EU Member States and companies set lower maximum levels, typically 1 ppm. Emissions are also covered by the ECVM Industry Charters.

Residual monomer in PVC

Trace amounts of un-reacted VCM can be found in PVC, but their concentrations are so low that processing and use of PVC products is perfectly safe. Food packaging and medical appliances require stringent safety measures; therefore the following specifications have been established.

Voluntary limit by ECVM member companies

In 1995, as part of the Industry Charter6, ECVM members agreed to set a limit of 1 gramme residual VCM/ton of suspension PVC sold for food or medical applications and 5 g/ton for suspension PVC sold for general purpose applications. In 1998, ECVM members committed to keep VCM concentration in final regular emulsion PVC product below 1 g/ton PVC (1)

Standards for medical equipment

Another example of measures on possible residual VCM is the case of medical PVC products including blood bags, liquid/blood transfusion sets, artificial heart lung apparatus and artificial kidneys.

The European Pharmacopoeia and other regulatory standards stipulate that the PVC material used in the production of medical devices must not contain more than 1 ppm VCM. In practice these devices typically contain less than 0.01 ppm VCM.

Standards for food contact applications

In January 1978 Directive 78/142/EEC set a limit of 1 mg VCM/kg for all materials and articles that are intended to come into contact with foodstuffs. The same directive states that vinyl chloride should not be detectable in foodstuffs by a specified test method, which has a detection limit of 0.01 mg/kg (10 ppb).

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