Surface treatment of metals and plastic




General Section



Manufacture of rubber products
Manufacture of plastics products, including compounding and conversion
Manufacture of fabricated metal products, except machinery and equipment
General manufacturing, e.g. machinery, equipment, vehicles, other transport equipment


Chelating agent
Plating agent


Industrial spraying
Roller application or brushing
Non industrial spraying

Product category

Metal surface treatment products
nin-metal-surface treatment products




This document describes the best available techniques for surface treatment of metals and plastics. Substitution possibilities for EDTA, PFOS, zinc cyanide, copper cyanide and hexavalent chromium are mentioned.

Substituted substances

Perfluorinated compounds (PFC)

CAS No. EC No. Index No.

Chemical group

Perfluorinated compounds

EDTA (ethylenediaminetetraacetic acid)

CAS No. 60-00-4 EC No. 200-449-4 Index No. 607-429-00-8

Chemical group

Acetic acid

Classification: hazard statements

H319 Causes serious eye irritation

Chromium hexavalent

CAS No. 18540-29-9 EC No. Index No.

Chemical group

Chromium compounds

Other adverse effects

The substance is: 1 carcinogen (IARC),  as listed in the Substance Database according to SUBSPORT Screening Criteria (SDSC).

Reliability of information

Evidence of assessment: there is evidence of an official (positive) assessment of the substitution

Reason substitution

other reasons

Other type of alternative

The document also describes non-chemical alternatives to many processes

Hazard Assessment

Substances to be substituted: Hexavalent chromium compounds are included in SUBSPORTplus´s database of hazardous substances. Perfluorinated compounds (PFC) and EDTA (ethylenediaminetetraacetic acid) are not included in SUBSPORTplus´s database of hazardous substances. EDTA causes serious eye irritation. PFC has no harmonised classification according to Annex VI of Regulation (EC) No 1272/2008 (CLP Regulation). Alternative substances: There is no further information on the alternatives.

Description of Substitution

In this document the chemicals used in installation for surface treatment for metals and plastics using an electrolytical or chemical process are assessed in order to describe the best available techniques (BAT). SUBSPORTplus will only shortly mention the substitutions in the document. For more information please look in "Further information". The document can be obtained for free from the link. The following substitutions are mentioned: EDTA Chelating agents such as EDTA and NTA are often used in degreasers and etchants used for printed circuit boards. They may be replaced by biodegradable ones - for example based on gluconic acid. PFOS Perfluorooctanes sulphonate is used as a foam suppressant and surfactant especially in the prevention of mists in hexavalent chromium electroplating and in alkali non-cyanide baths. The document mentions, that substitutes should be available for anodising, but no specific chemical is described. Zinc cyanide Instead of using zinc cyanide solutions the best available technique is acid zinc. This gives an optimum energy efficiency and reduced environmental emissions. Where metal distribution is important alkali cyanide-free zinc is the best available technique. Some products may contain PFOS. Copper cyanide Copper cyanide is used in strike plating on steel and zinc die casts. It can be substituted by acid copper, which is the choice in Germany. Pyrophosphate copper can also be used, but has limited applications. No alternatives are found for brass and bronze. Hexavalent chromium For decorative chromium plating hexavalent chromium can be replaced by trivalent chromium. Sealers and phosphochromate finishers can contain hexavalent chromium. Many of these can be replaced with non-Cr 6 solutions based on for example silanes, zirconium and titanium.

Case/substitution evaluation

It is not possible for SUBSPORTplus to evaluate the alternatives, as the information is not specified enough in the document.

State of implementation

In use

Type of information supplier


Further information

"Bref document" http:

Publication source: author, company, institute, year

Reference documents on best available techniques for surface treatment of metals and plastics. European Commission, August 2006.

Publication source

Type of publication and availability

Date, reviewed

December 11, 2020