New carpet always has a distinct odor that’s all its own.
Some like it and some dislike it – even fear it – intensely. Foremost you
should understand that there is no natural latex used in carpet today.
Therefore, carpet has none of the latex proteins that cause allergic reactions
in sensitive people, as might be the case with latex gloves. Let’s all agree to
participate in stifling that particular consumer myth about carpet, if nothing
And no, there isn’t any formaldehyde in carpet! Hasn’t been for almost 50 years and even back
then, it was used as a microbial inhibitor in amounts well below thresholds
considered safe for humans to breathe.
Back to new carpet odor…
A by-product produced by combining styrene and butadiene
monomers during the manufacture of styrene butadiene latex (SBL) is
4-phenylcyclohexene (4-PC). This is the “new carpet odor” that consumers notice
when carpet is first installed, but which usually disappears within 24-72 hours
with proper ventilation. Its effect is minimized or eliminated by turning on
the HVAC system and open windows as practical.
4-PC has generated much controversy for years and has been
blamed for many adverse responses in animals and humans. In every case, other
causative factors were also present. After extensive testing the U.S. EPA has
stated that, “4-PC is an unremarkable chemical . . .” and that “Regulatory
authority was not warranted.”
Regardless, carpet manufacturers have voluntarily taken steps to
considerably reduce 4-PC emissions from new carpet.
So why do some customers experience allergic reactions when
new carpet is installed?
The problem really isn’t with the new carpet. In reality
it’s the old carpet that was improperly disengaged and removed by the installer
that’s the culprit. So what can be done to prevent allergic reactions when “new
carpet” is installed?
Foremost, carpet retailers should inform purchasers of new
carpet about its distinct, albeit harmless odor, along with strategies for
minimizing its impact (basically, ventilation). Carpet volatile organic
compounds (VOCs; e.g., 4-PC) should be “aired out” before being transported to
the job site, but in some cases, this may not be practical.
Weather permitting, the installation area should be ventilated
with forced airflow before and during installation, and after installation for
72 hours. But imagine trying to do this with outdoor temperature extremes. With
moderate weather conditions, however, this is a highly practical way to prevent
allergic reactions during carpet installation – whether real or imagined.
Existing carpet should be vacuumed thoroughly before it is
disengaged and removed - but does an installer or customer ever do that? If possible, it is best to exhaust the vacuum
outside the structure. In fact, this may even be a good service for a
professional cleaner with a truck-mounted plant to offer to customers.
Rather than the installer grabbing a corner and running out
the door, old carpet should be cut into 4-to-6-foot-wide strips and rolled in
3-to-4-mil plastic sheeting to contain dust and soil during removal. Similarly,
cushion or under pad should be rolled carefully to trap fine particles of soil
that sift through carpet over time and can be easily aerosolized during pad
Subfloors should be vacuumed (never swept) using equipment
with high-efficiency filter bags that trap some 99% of particles at one micron.
Vacuuming should be part of the subfloor preparation procedure anyway.
Finally, consumers should be advised to ventilate their
structure during and for 48-72 hours after carpet installation. For the most
part, this should solve the problem.
When professionals hear consumers complain about “new
carpet” causing allergic reactions, they should be asked to consider the fact
that new carpet often comes with new fixtures and furniture. New furnishings,
adhesives and finishes can off-gas a variety of chemicals, including
formaldehyde, to which sensitive persons may react. This is the most likely
cause of allergic reaction when new carpet is installed, but that doesn’t mean
that the new carpet is the culprit.
Typically, it’s something else.