Research and analysis

Polyvinyl Chloride (PVC) additives: a scoping review - summary

Published 1 March 2024

Applies to England

1. Chief Scientist’s Group report summary

This project aimed to identify which polyvinyl chloride (PVC) additives are likely to be relevant to the UK market and to prioritise them based on readily available information. Additives are substances that PVC is blended with to confer various mechanical and chemical properties. Gaining information on them will help the Environment Agency to understand the risks that these additives pose to the environment and human health, and to prioritise those that may need further evaluation.

1.1 Background

PVC is one of the most widely used synthetic thermoplastics in the world. Thermoplastics are materials that become mouldable at high temperatures and solidify upon cooling. PVC is produced in both rigid (unplasticised) and flexible (plasticised) forms. To achieve the desired characteristics, the polymer is blended with other substances called ‘additives’. These are not bound to the polymer, so can be released to the environment under some conditions. Due to the widespread use and application of PVC, concern has been raised about the implications for the environment and human health from PVC additives.

1.2 Approach

A list of 228 additives of potential relevance to the UK was compiled from the scientific literature and information from the European Chemicals Agency (ECHA). Information collected on the substances included regulatory status, use type and tonnage, typical concentrations of the additives present within PVC, environmental and human health hazards, monitoring data, as well as supporting background information on the lifecycle of PVC and the potential for emissions at various lifecycle stages. A first-tier qualitative screen of these substances was performed to generate a relative  risk ranking (high, medium, low or no data).

1.3 Findings

Most additive emissions are likely to occur during the service life of PVC. The concentration of additive in the PVC, its physicochemical properties and the associated polymer matrix all influence the potential for release. Other significant factors include the product’s life span and the environmental conditions that the material is exposed to (e.g., indoor or outdoor use).

The 27 substances flagged as being of the highest priority function as flame retardants, heat stabilisers, pigments, plasticisers or slip promoters. Only 3 of these are not currently under regulatory scrutiny: tributyl citrate (CAS 77-94-1) (flagged primarily for human health concerns), N-butyl benzene sulfonamide (CAS 3622‑84‑2) and (Z)-N-octadecyldocos-13-enamide (CAS 10094-45-8).  

Given its widespread detection in surface waters, triphenyl phosphate is a candidate for further risk assessment in the UK. It is used in a variety of materials and is also an impurity in other flame retardants, so this work would extend beyond the use of PVC. Further consideration could be given to reviewing the plasticiser bis(2-ethylhexyl) adipate for similar reasons.

Di-2-ethylhexyl phthalate is also widely detected but is subject to authorisation in the UK and is also restricted in PVC used indoors. However, there are no controls on imported or recycled PVC articles for use outdoors (such as rainwater collection systems, traffic management infrastructure, hoses, etc.). The continuing widespread detection of this substance could be due to historical uses, but a campaign to measure its presence in imported / recycled articles for use outdoors could provide insight as to whether further controls might be warranted. 

Tris(2-ethylhexyl) phosphate, 2‑ethylhexyl diphenyl phosphate and (1,1’-(ethane-1,2-diyl)bis[pentabromo-benzene]) have been detected in indoor dust, so they are of interest from a human health perspective and could be candidates for further assessment.

1.4 Publication details

This summary relates to information reported in detail in the following output:

• Title: Polyvinyl Chloride (PVC) Additives Scoping Review
• February 2024
• Project manager: Dr Kofi Renner, Chemicals Assessment Unit, Chief Scientist’s Group

This project was commissioned by the Environment Agency’s Chief Scientist’s Group, which provides scientific knowledge, tools and techniques to enable us to protect and manage the environment as effectively as possible.

Enquiries: research@environment-agency.gov.uk.

© Environment Agency