Richard Denison, Ph.D., is a Senior Scientist.

In recent days, two compelling cases have surfaced of so-called “regrettable substitutions” – industry responding to concerns about the use of one dangerous chemical by replacing it with another that is less well-studied, or at least not currently in the crosshairs.

Case 1:  Chinese manufacturers of children’s jewelry, responding to concerns and restrictions on the use of lead in such products produced for export to the U.S., have replaced it with cadmium, a known human carcinogen and developmental toxicant that, if anything is even more toxic to kids than lead – but is not subject to any restrictions in such kids’ products. 

Case 2:  American food product manufacturers, responding to concerns about the devastating effects on the lungs of workers exposed to diacetyl – an artificial butter flavoring used in many products, most notably microwave popcorn – have begun to replace it with closely related chemicals likely to break down into diacetyl or otherwise have similar effects.

Are we destined forever to play this dangerous variant on the game of whack-a-mole, or can something be done? Read more »

Cal Baier-Anderson, Ph.D., is a Health Scientist.

When it comes to chemical exposures, workers are on the front line.  Workers are usually the most likely to be exposed to harmful levels of chemicals, because they are the ones producing, processing, handling, sampling and measuring, transferring and transporting chemicals in larger and more concentrated quantities. 

Throughout history, workers have been the canaries in the coal mines; the first to exhibit the health effects of hazardous chemical exposures, from scrotal cancer in chimney sweeps, to mesothelioma in shipyard and construction workers to liver cancer in vinyl chloride workers. 

For these reasons, EDF has argued that workers handling or otherwise likely to be exposed to nanomaterials must be protected from harm (see our earlier posts here, here and here).  Now, a new government study published in the respected journal Environmental Health Perspectives reveals that certain comfortable assumptions about nanomaterial laboratory safety may be downright wrong. Read more »

Richard Denison, Ph.D., is a Senior Scientist.

Some months ago, my colleague John Balbus posted here about studies finding that when multi-walled carbon nanotubes (MWCNTs) are injected into the abdominal cavities of mice, they induce inflammation and mesothelioma-like reactions similar to those caused by asbestos.  He appropriately cautioned that – among other critical questions – these studies had not demonstrated that inhaled MWCNTs could actually move out of the lung and into the tissues where asbestos gives rise to its effects.  Well, that particular dot now appears to have been connected. Read more »

Cal Baier-Anderson, Ph.D., is a Health Scientist.

In 2004, Gunter Oberdorster and colleagues demonstrated that upon inhalation, ultrafine particles, the dimensions of which are measured in nanometers, can move from the nasal passages of rodents to the brain via a specialized nerve called the olfactory bulb.  The evolutionary purpose of the olfactory bulb is to relay information about odors directly and rapidly from the nose to the brain. 

The extent to which rapid transit via the olfactory bulb is a significant potential route of exposure to engineered nanomaterials is still an open question.  But two new papers add support for the relevance of this intriguing exposure pathway, raising important questions regarding the safety of inhaled nanoparticles. 

Read more »

Richard Denison, Ph.D., is a Senior Scientist.

My last post identified two Section 8(e) "substantial risk" notices pertaining to carbon nanotubes, one submitted by BASF, the other by Arkema.  I have in my files one additional Section 8(e) notice for a single-walled carbon nanotube (SWCNT), submitted by DuPont.  With three Section 8(e) notices submitted for different rat pulmonary toxicity studies on carbon nanotubes, it's interesting to compare their results. Read more »

Richard Denison, Ph.D., is a Senior Scientist.

Since my first post concerning EPA's Consent Order, I've been reflecting further on the management conditions it imposes – or, more accurately, on what conditions it doesn't impose.  The Order's only such conditions address potential worker exposure.  What about the rest of the nanomaterial's lifecycle? Read more »

Richard Denison, Ph.D., is a Senior Scientist.

[Part II of this post is available here.] 

Word hit the street today that EPA intends to make public a "sanitized" version of a Consent Order it has negotiated with a producer of multiwalled carbon nanotubes (MWCNTs).  [A link will be provided once available.]  We obtained a copy of the Order, which has redacted all information claimed confidential by the company involved.  What can we learn from this well-scrubbed Order? Read more »

John Balbus, M.D., M.P.H., is Chief Health Scientist.

A new study published today in Nature Nanotechnology finds that multi-walled carbon nanotubes (MWCNTs) cause inflammatory changes in mice that closely resemble those caused by asbestos.  This is the second study in a few months to make this finding.  (I posted on the first, Takagi et al., a few weeks ago.)  So is the case closed on multi-walled carbon nanotubes?  Or is too early to draw conclusions? Read more »

John Balbus, M.D., M.P.H., is Chief Health Scientist.

It’s been a worry for engineered nanoparticles. Now, a new study from the Harvard School of Public Health (Suglia et al., 2008) is the first to suggest that particulate air pollution not only damages the lungs and heart, but also may damage the developing brain.

Researchers measured cognitive function in over 200 children in Boston in relation to their residential exposure to traffic-related air pollution by measuring airborne carbon black particles. They found the IQ-lowering effect of higher exposure is comparable to a pregnant mother smoking 10 cigarettes a day or moderate lead exposure. Read more »