According to a study published earlier this year, German
scientists have found that cotton clothing containing high
levels of dioxins may be a significant source of both human
exposure and environmental contamination. The use of the
organochlorine pentachlorophenol (PCP) during the transport
of cotton may be a primary source of the dioxins. The
scientists feel that textile contamination accounts for the
presence of dioxins and furans in domestic sewage sludge, dry
cleaning residues and household dust, and also explains how
certain dioxins not found in the food supply accumulate in
humans.
...
Scientists also found that when RcleanS t-shirts were washed
with contaminated ones, 7% of the dioxin and furan content
was transferred to the clean shirts and 16% washed out into
the sewage system. The researchers measured dioxin levels in
household laundry runoff and estimated that they contributed
between 27-94% of total dioxin and furan inputs to a local
sewage treatment plant that handles primarily domestic
sewage. Shower and bath water was also found to contain
dioxins of textile origin washed from the skin, adding to
contamination of the runoff.
...
most treated cloth comes
countries where there are fewer restrictions on the use of
PCP...

Ever notice that everything you're wearing was made in China?

Dioxins from PCP Treated Cotton.