* EFSA says neonicotinoids may affect developing human brain
* Warning comes after some insecticides linked to bee deaths
* Bayer says findings based on inconclusive evidence
(Adds comment from Bayer, European Commission)
LONDON, Dec 17 European health authorities
warned on Tuesday that two insecticides, including a widely-used
chemical made by Bayer, may affect the developing
human brain and should be more tightly controlled to limit human
The products - acetamiprid and imidacloprid - belong to a
popular class of insecticides called neonicotinoids, which have
recently been in the spotlight due to links with plunging
populations of bees. Imidacloprid is one of the most widely used
insecticides in the world.
The European Union voted in April to ban three
neonicotinoids - including imidacloprid which is primarily
manufactured by Bayer - for two years amid safety and
In Tuesday's move, the European Food Safety Authority (EFSA)
recommended that guidance levels for exposure to the products be
lowered while further research is carried out to provide more
reliable data on so-called developmental neurotoxicity.
"Acetamiprid and imidacloprid may adversely affect the
development of neurons and brain structures associated with
functions such as learning and memory," EFSA said in a statement
from its Rome headquarters.
"Some current guidance levels for acceptable exposure to
acetamiprid and imidacloprid may not be protective enough to
safeguard against developmental neurotoxicity and should be
A spokesman for the European Commission, which asked EFSA to
carry out the assessment, said it would give Bayer and the
makers of acetamiprid an opportunity to comment on the findings.
"In principle, the next step would then be to amend the
reference values," said Commission health spokesman Frederic
Vincent, adding that EU government officials would begin the
process at a meeting in March.
In response, Bayer's CropScience division said it saw no
link between imidacloprid and developmental neurotoxicity in
humans, and said EFSA had based its concerns on an inconclusive
2012 study that used tests on rat cell cultures.
"EFSA itself recognises the limitations of this publication.
Bayer CropScience has also evaluated the publication and can
confirm that few conclusions can be drawn from it," the
(Reporting by Kate Kelland, additional reporting by Charlie
Dunmore in Brussels; editing by William Hardy and Tom Pfeiffer)