© 2016 SATRA Technology Centre. Reproduction of SATRA Spotlight in part or in its entirety is not permitted in any shape or form, whether in print or digital media, without prior written permission from SATRA.
Leather chromium VI
failures
European restrictions are
now in force for the
maximum amount of
chromium VI in
leathergoods.
Tanning is the process of making raw hides
or skins imputrescible (not subject to decay)
by converting them into leather. The
majority of leathers used in furniture, gloves
and footwear are tanned using chromium
salts. This type of tannage is very popular
because of the favourable properties of the
resultant leather – namely, high stability at
high temperatures even when wet and
better grain crack resistance than
vegetable-tanned leathers.
Chromium tanning uses chromium III
salts which are not considered to be
harmful when in leather. On rare
occasions, these chromium salts could be
contaminated with chromium VI. Also,
under specific conditions, chromium VI can
form in the leather post-production.
Chromium VI is a hazardous form of
chromium, therefore new European
legislation (Regulation (EU) No 301/2014)
which extended the restrictions in REACH
(EC) No 1907/2006 annex XVII) was
enacted on 1st May 2015 and has
restricted its presence in leather that comes
into contact with the skin.
Product recalls
No matter where products are on sale in
the world, companies placing product on
the marketplace have a responsibility to
ensure that product is safe for the
consumer. Where products are proven not
to be safe, product recalls and litigation can
follow. The European ‘rapid alert system’ for
dangerous consumer products (RAPEX) is a
website on which the EU Commission
publicises information reported by national
authorities on products considered to pose
a serious risk to consumers.
In 2014, there were 107 entries for
shoes, boots and gloves and 77 per cent of
these entries cited chromium VI as the
reason for their entry. Of the 19 entries for
gloves, nearly 80 per cent cited chromium
VI and there was a similar percentage for
shoes and boots. All these entries are
classified as a serious risk level and the
three countries making the majority of these
notifications were some of the largest
consumer markets in Europe: Germany,
France and Spain.
Although there was no specific
legislation across the whole of Europe
which restricted the amount of chromium VI
in consumer goods, these products were
withdrawn from the marketplace in these
© 2016 SATRA Technology Centre. Reproduction of SATRA Spotlight in part or in its entirety is not permitted in any shape or form, whether in print or digital media, without prior written permission from SATRA.
countries under the General Product Safety
Directive (2001/95/EC).
The dangers of chromium VI
There are both acute (short-term) and
chronic (long-term) effects from contact
with substances containing chromium VI.
Inhalation poses the greatest acute danger,
as the respiratory tract is the major target
organ and causes shortness of breath,
coughing and wheezing. Contact with the
skin can cause burns and contact dermatitis
allergic reactions, which appear as
reddening of the skin, itching and rashes.
A chronic effect from chromium VI
skin exposure is the formation of ulcers,
but the greatest danger is an increased
risk of lung cancer and lung tumours
through the inhalation of chromium VI.
Also, as chromium VI is a skin sensitiser,
future reactions can be caused when only
a very small amount is in contact with the
skin. Inhalation is obviously not a
significant risk with leather in consumer
goods, but there are dangers from
ingestion. This is a particularly important
hazard to assess for young children’s toys
or apparel where there is a risk of
mouthing. Studies have shown the
ingestion of chromium VI may affect the
liver, kidneys and the immune system.
Chromium chemistry
Chromium is a transition metal and can be
found amongst the d-block elements in the
periodic table. Due to the specific
arrangement of electrons, transition metals
can be present in compounds and aqueous
complexes at different oxidation states, also
called ‘valences’. This usually results in
transition metal compounds and
complexes having characteristic colours.
Chromium III compounds are generally
green and chromium VI compounds yellow,
orange or red.
A chromium III salt (typically chromium
sulphate) is used as a tanning agent as this
cross-links the collagen fibres of the animal
skins or hides to make them resistant to
rotting. Chromium III is an essential trace
mineral in the human diet at the levels
normally encountered and does not cause
an undue risk to human health. Chromium
VI compounds, however, are very different.
These could be present either as impurities
in the original tanning salts, by the chemical
oxidation of chromium III during the tanning
process or in the leather after tanning.
High temperatures, ultraviolet light and
strongly alkaline conditions are thought to
favour the reaction mechanism from
chromium III to chromium VI. However, as
chrome-tanned leather is a naturally acidic
material, this reduces the likelihood of
conversion to chromium VI in finished leather.
Regulation (EC) No 301/2014
Before May 2015, the only chromium VI
restriction applicable to leather was for its
Leather’s versatility makes it a suitable material for a wide range of products
use in personal protective equipment (PPE).
The restriction in REACH Annex XVII
relating to chromium VI only covered
building cements where, due to the small
particle size of building cement dust, there
could be a significant risk of inhalation.
Now the restriction has been extended to
include leather articles or leather parts of
articles that come into contact with the skin.
The maximum amount of chromium VI
must be below 3mg/kg (0.0003 per cent)
of the total dry weight of leather. This
concentration is the detection limit of EN
ISO 17075 – the only internationally
recognised analytical method currently
available to detect chromium VI in leather.
The restriction does not apply to leather
articles or articles containing leather that
were in end-use before May 2015.
Testing for chromium VI
Testing is an essential tool for
demonstrating compliance with the General
Product Safety Directive and Regulation
(EC) No 301/2014. In addition to testing
leather when it is received from the tannery,
it is strongly recommended that some final
product is also part of a testing programme
due to the complex chemistry of chromium
and its conversion between chromium III
and VI. Here at SATRA, we saw an increase
in the amount of chromium VI testing as
the 1st May 2015 date for the new
legislation drew closer. Although most
leathers contained less than 3mg/kg, there
has been an increase in the failure rate,
albeit this is still low. With this new
regulation now in place, the 2014 product
withdrawals in Germany, France and Spain
published on RAPEX and legal obligations
under the General Product Safety Directive,
it is more important than ever to include
testing of final products as part of a due
diligence testing regime.
How can SATRA help?
Please email [email protected] for
further information or assistance with the
testing of leather and leathergoods for
the presence of chromium VI.