Science Saves Lives

This op-ed was co-authored with Marc Shaffer and originally appeared in Environmental Health News.

“Nothing is so frightening as what’s behind the closed door… The audience holds its breath along with the protagonist as she/he (more often she) approaches that door. The protagonist throws it open, and there is a ten-foot-tall bug. The audience screams, but this particular scream has an oddly relieved sound to it. ‘A bug ten feet tall is pretty horrible’, the audience thinks, ‘but I can deal with a ten-foot-tall bug. I was afraid it might be a hundred feet tall’.”

– Stephen King, Danse Macabre

Right now, we are in the COVID-19 corridor, holding our breath as we approach Stephen King’s closed door.  Every day brings news of more cases, more deaths, more restrictions, and more fear.  

Coronavirus is terrifying – and more so because we, as a nation, seem woefully unprepared.  In 2018, the White House National Security Council removed the official in charge of responding to global pandemics and dissolved the global health security team he oversaw

This is just one example of President Trump’s contempt for science.  

His dangerous disregard for the truth—not just with regard to this virus, but also for air pollution, pesticides, and other environmental public health hazards—is placing all of us at risk.  

Lives saved 

Consider a different airborne killer—air pollution. According to new research released in early March,  human-generated air pollution kills more than 5 million people around the world—each year.  

But it used to be worse.

There was a time, not so long ago, when Los Angeles was shrouded in thick, sickening clouds of smog. In some cities in the eastern U.S., pollution reached levels double that of the worst days in modern Beijing, one of the most polluted cities in the world. Among the primary causes were emissions from industrial facilities, coal power plants, and vehicle tail pipes. 

Using science as their guide, legislators from both parties came together to improve air quality around the country. A major breakthrough came with the Clean Air Act, signed into law by President Nixon in 1970 and strengthened under President Bush in 1990.

Since 1990, as the U.S. population has grown by 30 million, the numbers of registered vehicles by 80 million, and the size of the nation’s economy has quadrupled, air pollution emissions have dropped by more than 70 percent, preventing more than 4.2 million deaths

Science saves lives.  

Yet, President Trump is undoing it all

Ignoring science 

In February, just as coronavirus fears were escalating, the Trump Administration released its 2021 budget.  It calls for cutting U.S. Environmental Protection Agency funding by 26 percent, a reduction that will severely hamper the agency’s ability to conduct cutting-edge research and implement programs that will save lives and improve the health of millions of Americans.

The administration has repealed President Obama’s Clean Power Plan, a move that is expected to cause 5,200 premature deaths per year by 2030 by increasing the amount of carbon emissions from coal-fired power plants we will breathe. The administration has also opened the door to greater mercury emissions from coal-fired power plants, eliminating protections that the Obama Administration had estimated would prevent 11,000 premature deaths

As for those tailpipes that contributed to L.A.’s old toxic haze, Trump is preparing to roll back standards for vehicle emissions and has already revoked California’s ability to set more stringent vehicle emission rules and allowed unrestricted use of a gasoline blend that will increase levels of smog. EPA’s programs to control smog and other vehicle-related emissions save 40,000 lives each year

Eerily echoing the dismantling of the pandemic response team, the Trump EPA has disbanded the longstanding expert panel that provides guidance for national standards under the Clean Air Act. Without its input, the EPA  has ignored the newest science, sticking with an outdated standard for particulate matter that will cause thousands of additional premature deaths per year

When the coronavirus threat is defused—as it surely will be—we will still face airborne killers.  Our only effective protection against the familiar foe of air pollution, the monster we’ve seen, is prevention, reducing harmful emissions from sources like power plants and vehicles.  

Just as with our rush to contain the coronavirus, our lives depend on it.

Re: “A Love Letter to Canned Foods”

Last week, The New York Times published an article in their Food section highlighting meal ideas based on canned food. In response, Dr. Leonardo Trasande (NYU) and I wrote a letter to the editor with some of our concerns. This letter did not get published, so I’m posting here instead.

As avid cooks, we love reading columns from Melissa Clark. But as environmental health researchers, we were concerned that her recent piece, “A Love Letter to Canned Food,” fails to discuss potential health concerns associated with metal cans. Their linings contain bisphenols, such as bisphenol-A (BPA), or the wide array of “regrettable substitutes,” which can interfere with our body’s hormones and disrupt our developmental, reproductive, neurological, and immune systems. All of this is described in our American Academy of Pediatrics technical report and policy statement on “Food Additives and Child Health.” For canned food to continue to be a convenient, affordable and nutritional option for feeding our families, we need systemic policy changes that ensure that any additives are fully tested for safety prior to use in the marketplace. Our own work suggests that replacing BPA in cans with safer alternatives may produce economic benefits to society greater than the costs.  

Rachel M. Shaffer, MPH
PhD Candidate, Environmental Toxicology
Department of Environmental and Occupational Health Sciences
University of Washington School of Public Health

Leonardo Trasande, MD, MPP
Jim G. Hendrick, MD Professor and Vice Chair, Department of Pediatrics
Chief, Division of Environmental Pediatrics
Professor of Environmental Medicine & Population Health
NYU School of Medicine

The Big Chart of Federal Chemical Evaluations & Assessments

Today, I’m excited to share an infographic that I made, depicting all of the different chemical evaluations and assessments that various federal agencies (in the U.S.) conduct.

If you want to hear about the backstory & process for creating this, read on below.

Otherwise, here’s a link to a PDF version of the graphic. There are hyperlinks throughout, if you want to explore any of the information further. Yes, I know this is very detailed; it is meant to be digested by zooming around to different sections of the graphic.

I’ve tried to be as accurate as possible. But if you catch something that doesn’t look right, please let me know.

I hope this helps the environmental health community (and others who might be interested) better understand the review processes that are intended to keep us safe (unless/until politics get in the way…).

The backstory

In April, the Agency for Toxic Substances and Disease Control (ATSDR) released a draft ToxProfile for glyphosate. If you’ve been following this blog, you know that I’ve been paying a lot of attention to glyphosate lately (see some of my recent posts here and here). Given my interest in this topic, I decided to review the document and take the opportunity to prepare public comments.

[What are public comments, you might ask? Public comments are a way for the public to provide feedback during the federal rulemaking process. Under the Administrative Procedure Act (1946), whenever a federal agency develops a new regulation, they are required to solicit input from the public. (For more on the public comment process and how you can get involved, check out the Public Comment Project!)]

As I was reviewing ATSDR’s ToxProfile, I realized that I did not fully understand how this effort was distinct from EPA’s assessment of glyphosate. ATSDR and EPA are two separate federal agencies with different missions, so clearly these assessments served different purposes.

I soon realized that elucidating this distinction was just one part of a larger story. So, I decided to create a master chart to better understand all of the different types of reviews, evaluations, and assessments that different federal agencies conduct, the main purposes of these evaluations, and what other processes or regulations they might relate to.

The process

Some of the agency assessments were quite familiar to me or fairly well-explained online; for example, those that EPA is supposed to conduct under the recently reformed Toxic Substances Control Act. It was surprisingly hard to get clear information on other assessments and related agency activities, however (even for me, someone who is relatively well-versed in this field). Specifically, I found the online information for the Occupational Safety and Health Administration (OSHA), the National Institute for Occupational Safety and Health (NIOSH), and the Consumer Product Safety Commission (CPSC) to be a bit confusing. I actually ended up calling several people at these agencies (using phone numbers listed online) to get clarifying information. (Thank you to those federal employees who picked up my cold calls and answered my questions!)

I started collecting this information in an excel chart, but this format is not very conducive to easy online reading or sharing. So, I decided to challenge myself to make an infographic, which I had never done before. I experimented with various online tools before settling on, which I also used to make the timeline in the glyphosate meta-analysis. I’ll spare you the details, but let’s just say, this took me a LONG time (sorry, dissertation, I’ll get back to you soon).

I imagine that I’ll continue to refine this over the next few months/years. If you see anything that looks wrong or have suggestions for improvement, let me know.

Ignorance is not bliss for “inert” pesticide ingredients

One of the complicated parts of assessing the hazards and risks of glyphosate is that the product that everyone uses (for example, Round-Up) is not just glyphosate. The active ingredient is glyphosate, but the final formulation sold in stores is a combination of glyphosate and other “inert” ingredients.

[Note: I’m going to stubbornly use quotation marks around the words “inert” throughout this article, to emphasize my point that this is not an accurate characterization. “Inert” implies inactive, which is not true. Read on for more.]

These “inert” ingredients are subject to essentially no testing, disclosure, and regulatory requirements, even though they almost always make up a larger percentage of the final product than active ingredients. And, evidence indicates that combinations of the “inert” and active ingredients can actually be more toxic than the pure active compound (for example, see here, here, and here).

A new publication by Mesnage et al. in Food and Chemical Toxicology reviews the problems with the status quo and the implications for health effects research. Given the relevance of this topic to my previous blog posts on glyphosate (see here and here) and pesticides in general, I’ll summarize some of the authors’ key points below.

But first, some terminology: what is the difference between active and “inert” pesticide ingredients?

Under the U.S. Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), an active ingredient is one that is intended to be toxic to the target species. For example, glyphosate, the active ingredient used in glyphosate-based herbicides (GBHs), blocks an essential enzyme pathway in plants. All other ingredients in a pesticide product, often added to improve effectiveness, are classified as “inert.”

Abounding uncertainty about “inerts”

Contrary to what their name suggests, however, “inert” ingredients may not actually be inert. In fact, the U.S. Environmental Protection Agency (EPA) explicitly states that this designation “does not mean non-toxic.”

But, it’s challenging to get extensive and accurate information about these chemicals because:

  • Neither the “inert” ingredients nor the final formulations (the combination of active + “inert” ingredients) are subject to most standard regulatory toxicity tests, such as evaluation of cancer and reproductive effects. As a result, pesticide approvals are based on the unrealistic scenario of exposure to the active ingredient alone.
  • Companies can routinely claim the identity and concentration of these “inert” ingredients as confidential business information (CBI). That is why you’ll often see labels like the extremely vague one below. As a result, it’s difficult – actually, essentially impossible – for scientists to independently evaluate possible toxicity. We are kept blind to these final products.

Image: Beyond Pesticides

  • Because we don’t know the identity of these “inert” ingredients, there are essentially no monitoring data on environmental or human exposure.

So, in summary, we don’t know how toxic the “inert” ingredients or final formulations are; the identity of these “inert” ingredients is kept secret from the public; and we aren’t monitoring any of these chemicals for their presence in our bodies or the environment.

All of this makes it challenging for the EPA to conduct accurate pesticide risk assessments, which require information on both hazard (ie: toxicity) and exposure.

Constant change 

An added barrier is that companies often change their formulations over time and across regions. Apparently, there are usually between 100-150 different formulations of GBHs on the market at any given time, and over 2000 different varieties have been registered in Europe since 2012.

How are we supposed to evaluate the health effects of such a moving target? Robust epidemiological studies require precise definitions of exposure (referred to as the “consistency” principle) to prove causality. In essence, the exposure under investigation should be defined very specifically, such that it is not possible for variations in versions of the exposure to have different effects, which could muddy the overall conclusion of the study.

(As a concrete example, think about investigating the impact of “exercise” on health. Exercise is very broad, so it wouldn’t be helpful or informative to evaluate the effect of general “exercise,” which could span everything from a 30-minute walk once per month to a 2-hour run each day. The effects of these different types of exercise could have very different impacts on health. So, a better study question would be focused on a more specific type of exercise.)

For pesticide epidemiology, all of these changing formulations make it very challenging to draw conclusions on health effects across time and space. It’s quite likely that one study based in multiple locations could be evaluating the effects of different products at the same time. A study looking at one region over a period of several years also faces the same problem. As the authors of the recent publication stated, “formulated GBHs with the same product name from different countries may not be the same mixture of chemicals, nor the same as the brand-name product bought previously, or in the future.”

This is one possible reason for differing conclusions about hazard, and it makes reproducibility nearly impossible.

Overcoming INERTia 

The authors put forth a few suggestions to improve this murky situation. Some can be acted on by researchers now, such as including detailed product information (ex: trade name, dates of manufacture, product ID number) in the methods sections of their papers, to facilitate reproducibility and comparison across studies.

Other proposals will need to wait until there is political will for policy change. Most important is the need for full public disclosure of pesticide product composition. (By the way, back in 1997, the American Medical Association urged Congress to “support all efforts to list both active and inert ingredients on pesticide container labels.”) The authors also suggest monitoring of food and feed for concentrations of the “inert” ingredients (that is, if we can get access to information about their identities!), so we can understand patterns of exposure.

Additionally, it is essential to revise the pesticide approval processes to include full testing of “inert” ingredients as well as the final formulated products. We urgently need a regulatory system that accounts for these real-world exposures.

It’s high time for transparency on these formulations and their effects on human health and the environment.

Concerning Glyphosate

Apologies for the long blog absence. I’ve been busy PhD-ing (including preparing for and passing my oral general exam!) and working on various side projects.

One of those side projects has been focused on glyphosate. Glyphosate, the active ingredient in Monsanto’s (now owned by Bayer) Roundup, is the most widely used herbicide in the world. First marketed in 1974, its usage skyrocketed after the introduction of “Roundup-ready” (i.e.: Roundup resistant) crops in 1996 and the practice of “green-burndown” (i.e.: using the chemical as a desiccant shortly before harvest) in the mid-2000s. In 2014, global usage was estimated to be 1.8 billion pounds.  

But these staggering statistics are not the only claim to fame for glyphosate. It has also been the subject of intense international regulatory and scientific scrutiny in recent years, for its possible link to cancer. The stakes are high (billions of dollars for Monsanto, related to sales of both the herbicide itself and its line of herbicide-resistant crops), and the conclusions are controversial.

Carcinogenic or not, that is the question.

In 2015, the International Agency on Cancer (IARC) declared that glyphosate was a “probable human carcinogen” (relevant links: explanation of IARC classifications; official summary for glyphosate; IARC webpage with follow-up links). However, that same year, the European Food Safety Authority (EFSA) concluded that “glyphosate is unlikely to pose a carcinogenic hazard to humans, and the evidence does not support classification with regard to its carcinogenic potential.” In 2016, the US Environmental Protection Agency (EPA) determined that glyphosate was “not likely to be carcinogenic to humans at doses relevant for human health risk assessment.”

Ok, so that’s confusing. How did these agencies, all of which are supposed to conduct unbiased reviews of all of the evidence come to such different conclusions? There have been several recent publications that explain these inconsistencies (for example, see here and here). In essence, it boils down to: 1) differences in how the agencies weighed peer-reviewed, publicly available studies (most show adverse health effects) versus unpublished regulatory studies submitted by manufacturers (most do not show adverse health effects); 2) whether the agencies focused on studies of pure glyphosate or the final formulated glyphosate-based product that is used in agricultural applications (which is known to be more toxic); and 3) whether the agencies considered dietary exposures to the general population only or also took into account elevated exposures in occupational scenarios (i.e. individuals who apply glyphosate-based herbicides in agricultural settings).

Meanwhile, as the debate continues… 27 countries (as of November 2018) have decided to move forward with implementing their own bans or restrictions. And, Monsanto/Bayer faces more than 9,000 lawsuits in the US from individuals who link their cancer to the herbicide. (The courts ruled the first case in favor of the plaintiff, though Monsanto is appealing the decision).

My connection

This highly contentious area is outside the topic of my dissertation research, but I got involved because my advisor was a member of the EPA scientific advisory panel that reviewed the agency’s draft assessment of glyphosate in 2016. The panel’s final report raised a number of concerns with EPA’s process and conclusions, including that the agency did not follow its own cancer guidelines and made some inappropriate statistical decisions in the analysis.

Because of their dissatisfaction with EPA’s report, my advisor and two other panel members decided to pursue related research to dig further into the issues. I enthusiastically accepted the invitation to join.   

Our collaborative group recently published two review papers on glyphosate. I’ll provide brief highlights of both below.

Reviewing our reviews, part 1: exposure to glyphosate  

In January 2019, we published a review of the evidence of worldwide exposure to glyphosate. Even though glyphosate-based products are the most heavily used herbicides in the world, we were surprised (and dismayed) to find less than twenty published studies documenting exposure in only 3721 individuals.

So, our paper mostly serves to highlight the limitations of the existing data:

  • These studies sampled small numbers of individuals from certain geographic regions, mostly in the US and Europe, and therefore are not representative of the full scope of global exposures
  • Most studies relied on a single urine spot sample, which does not represent exposure over the long term and/or in different agricultural seasons
  • The occupational studies only covered 403 workers in total, a serious deficiency given its widespread agricultural use. Few assessed exposure before and after spraying; and no studies evaluated patterns related to seasonality, crop use, etc.
  • Only two small studies evaluated how population exposure has changed over time. So, we definitely don’t know enough about whether the dramatic increases in global usage have resulted in similarly dramatic increased concentrations in our bodies. (Presumably, yes).  

In addition to highlighting the need to address the points above, we specifically recommended  incorporating glyphosate into the National Health and Nutrition Examination Survey (NHANES), a national survey that monitors exposure to many chemicals – including other common pesticides. This is an obvious and fairly straightforward suggestion; in reality, it’s quite bizarre that it has not already been incorporated into NHANES. Testing for glyphosate would allow us to better understand exposure across the US – which is not reflective of global levels, of course, but an important start.

Reviewing our reviews, part 2: glyphosate & non-Hodgkin Lymphoma (NHL)  

Our second paper, published earlier this week, was a meta-analysis of the link between glyphosate exposure and non-Hodgkin Lymphoma (NHL). Yes, diving right in to the controversy.

There had already been several prior meta-analyses that showed an association between glyphosate and NHL, but ours incorporates new research and applies a method that would be more sensitive to detecting an association.

A meta-analysis combines results from separate studies to better understand the overall association. While they technically do not generate any “new” data, meta-analyses are essential in the field of public health. A single study may have certain weaknesses, focus only on selected populations, or reflect a chance finding. In drawing conclusions about hazards (especially in this scenario, affecting millions of people and billions of dollars), we want to look across the collection of data from many studies so we can be confident in our assessment.

We were able to include a newly published follow-up study of over 54,000 licensed pesticide applicators (part of the Agricultural Health Study (AHS)). Compared to an earlier paper of the same cohort, this updated AHS study reports on data for an additional 11-12 years. This extension is important to consider, given that cancer develops over a long period of time, and shorter studies may not have followed individuals long enough for the disease to arise.

We conducted this meta-analysis with a specific and somewhat unusual approach. We decided to focus on the highly exposed groups in order to most directly address the question of carcinogenicity. In other words, we would expect the dangers (or, proof of safety: is it safe enough to drink?) to be most obvious in those who are highly exposed. Combining people who have low exposure with those who have high exposure would dilute the association. IMPORTANT NOTE: this approach of picking out the high exposure groups is only appropriate because we are simply looking for the presence or absence of a link. If you were interested in the specific dose-response relationship (i.e.: how a certain level of exposure relates to a certain level of hazard), this would not be ok.

Our results indicate that individuals who are highly exposed to glyphosate have an increased risk of NHL, compared to the control/comparison groups. This finding itself is not entirely earth-shattering: the results from prior meta-analyses were similar. But, it adds more support to the carcinogenic classification.

More specifically, we report a 41% increased risk. For comparison, the average lifetime risk of NHL is about 2%However, I want to emphasize that because our analytical method prioritized the high exposure groups, the precise numerical estimate is less important than the significant positive correlation. Basically, the purpose of this and other related assessments (like IARC’s) is to understand whether glyphosate is carcinogenic or not: this is a yes/no question. It is up to regulatory agencies to judge the scale of this effect and decide how to act on this information.

As with any scientific project, there are several limitations. In particular, we combined estimates from studies that differed in important ways, including their design (cohort vs. case-control), how they controlled for confounding by exposure to other pesticides, and which reference group they chose for the comparison (unexposed vs. lowest exposed). When studies are very different, we need to be cautious about combining them. This is another reason to focus more on the direction of the effect rather than the exact numerical estimate.  

Beyond the headlines

The news coverage of this work has focused on the overarching results (especially the 41% statistic), as expected. But I want to highlight a few other aspects that have been overlooked.

To better understand the timing of these studies in relation to glyphosate usage, we put together a timeline of market milestones and epidemiological study events.


This took me SO MANY HOURS.

Of note is that all of the studies conducted to date evaluated cancers that developed prior to 2012-2013, at the latest. Most were much earlier (80s, 90s, early 00s). As illustrated in the timeline, we’ve seen a huge increase in glyphosate usage since green burndown started in the mid-2000s. Yet none of these studies would have captured the effects of these exposures, which means the correlation should be easier to see in newer studies if/when they are conducted.

Also, as I mentioned above, we included the newly published AHS cohort study in our meta-analysis. One might expect the old and new AHS studies to be directly comparable, given that they were conducted by the same research group. However, our deep dive into both papers elucidated important differences; consequently, they are not directly comparable (see Table 8 of our paper). An in-depth discussion of these issues (and some of their potential implications) is a topic for a separate post, but there’s a clear lesson here about how important it is to carefully understand study design and exposure assessment methods when interpreting results.

Finally, two brief points on the animal toxicology studies, which we also reviewed in our paper because they provide complementary evidence for assessing hazard in humans. We discuss these data but did not conduct a formal pooled analysis (to combine results from separate but similarly designed animal studies), which would allow us to better understand overarching results from the animal studies. Anyone ready for a project?  

Additionally, in future animal toxicology studies, researchers should use the formulated glyphosate product that is actually used around the world rather than the pure glyphosate chemical that has been the focus of prior testing. There is growing evidence to suggest that the final formulated product is more toxic, perhaps due to the added adjuvants and surfactants. And this would allow for better comparisons to the human epidemiological studies, which assess effects of exposure to the formulated product.

Reflecting on the process

I had followed the evolving story on glyphosate with great interest for several years, so it was exciting to be part of these projects. Contributing to research with a real-world public health impact has always been a priority for me, and this high-profile research (affecting millions of people, billions of dollars) certainly fits the bill.

That being said, it was not an easy process. These two papers represent years of work by our group, which we did on top of our regular commitments. Collaborating with three researchers whom I had never met also proved challenging, since we did not have established rapport or an understanding of each other’s work and communication styles. So, in addition to gaining skills in conducting literature reviews and meta-analyses, I learned valuable lessons in group dynamics. 🙂

Given the high-stakes and high-profile nature of this work, we were extra meticulous about the details of this project. We knew that it would be scrutinized carefully, and any error could damage our credibility (especially worrisome for me, since I’m just establishing myself in my career). It took many, many rounds of review and editing to get everything right. A good lesson in patience.

Speaking of patience, I know that scientific research and related policy decisions take time. But I hope that these two projects can contribute to moving forward in a direction that protects public health.


The Minamata Convention: Can We Make Mercury History?

This post was originally published on

Last month, the Lancet Commission on Pollution and Health released a striking report estimating that pollution caused 9 million deaths worldwide in 2015 – 3 times more deaths than caused by AIDS, tuberculosis, and malaria combined. Air pollution was responsible for the vast majority of these deaths, but water and chemical pollution also contributed substantial burdens.

figure 5 from report
Global estimated deaths by major risk factor and cause, 2015; The Lancet Commission on Pollution and Health (2017)

One of the chemical pollutants highlighted by the Lancet Commission is mercury, a known neurotoxicant. The report discusses the dangers of mercury when used specifically in small-scale gold mining in low-income countries, yet populations across the world can also be exposed through fish consumption or consumer products, among other sources.

Well before the new Lancet report was released, the international community had recognized the dangers of mercury and had been working to develop policies to minimize exposure to this pollutant. In fact, on August 16, 2017, after sixteen years of work and negotiations, the Minamata Convention on Mercury entered into force.

This global treaty aims to protect human health and the environment from the toxic effects of mercury through restriction of mercury products and processes. It is the first new international convention in almost 10 years focused specifically on health and the environment. (Other previous treaties include the Basel Convention for hazardous waste, the Rotterdam Convention for pesticides and industrial chemicals, and the Stockholm Convention for highly persistent global pollutants).

The convention is named after the decades-long environmental health tragedy in Minamata, Japan. Residents and animals in this area developed severe neurological syndromes after eating seafood that had been highly contaminated with mercury from industrial pollution.


Why Mercury?

Mercury is a naturally occurring metal, and certain chemical forms (specifically, methylmercury and metallic mercury vapor) are highly toxic. According to the World Health Organization (WHO), mercury is one of the top ten chemicals of public health concern. The nervous system – and in particular, the developing brain – is highly vulnerable to mercury. Exposure can result in permanent neurological damage. (Remember the Mad Hatter from Alice In Wonderland?) Other organ systems, such as the lungs, kidneys, and immune systems, may also be affected. The United Nations Environment Programme (UNEP) has stated that there is no safe level of mercury exposure.

How Are We Exposed Today?

Mercury is emitted through both natural and industrial processes. Examples of natural processes that release mercury include rock weathering, forest fires, and volcanic eruptions.

However, this global treaty targets mercury from industrial and human processes. These include coal burning, waste incineration, consumer products, and small-scale gold mining. Because mercury emissions travel through air and water without regard to political borders, only an international treaty could truly be effective in addressing this pollutant.

Human exposure to mercury occurs through several possible routes, including consumption of contaminated fish, inhalation of mercury vapors from the air, or even from the use of mercury in dental fillings.

Convention Commitments

The 84 countries that have already ratified the treaty (and the many other countries anticipated to fully join in the near future) will be required to take the following steps by 2020:

  • Phase-out or reduce mercury from products such as batteries, certain light bulbs, cosmetics, and pesticides
  • Control mercury air emissions from coal-fired power plants, waste incineration, and related industrial processes
  • Reduce or eliminate the use of mercury in small-scale gold mining
  • Reduce or eliminate the use of mercury in chemical manufacturing processes

The convention also provides guidance for safe storage of mercury, waste disposal, and contaminated sites.

Threats to U.S. Progress and Compliance

The U.S. Environmental Protection Agency (EPA) aims to address mercury pollution through numerous programs and regulations. But now, some of those efforts are under attack or subject to delay – threatening our prospects for reducing mercury exposure and complying with the convention.

For example, the Mercury and Air Toxics Standards (MATS) rule, passed under the Obama administration, limits the amount of mercury released from coal-fired power plants. The D.C. Circuit Court of Appeals had planned to review the cost-benefit analysis for this regulation but recently decided to delay the case instead. The Trump administration may actually decide to repeal the regulation altogether rather than defend the rule in court.

The administration’s vocal support for revitalizing the coal industry and the proposed repeal of the Clean Power Plan would further reverse progress that we have made in reducing mercury emissions. Recent shifts away from coal in this country have led to decreased mercury emissions and declining mercury contamination in tuna – historically, a significant exposure route for the population.

The current administration may also review a 2015 rule that set standards for disposal of coal ash, a byproduct of coal combustion. Improper disposal of coal ash in landfills can result in release of mercury, among other toxic chemicals.

These steps are hugely disappointing. Tackling this global pollution problem requires global action, and therefore the U.S. must continue to take strong steps to reduce mercury use and releases.

During these tumultuous times in particular, the ratification of this global treaty is an important victory for human health and the environment – and a reminder that we can still come together to make progress towards global health and sustainability. But, the realization of these goals requires political will and cooperation from all parties, and only time will tell if they can follow through on these targets.

Getting the lead out of our skies


This article was written in collaboration with Dr. Steven Gilbert and originally posted in Environmental Health News. 

The excitement of watching sea planes take off and land from Lake Union, Seattle belies their hidden danger: leaded gasoline.

While lead was removed from automobile and other transportation gasoline more than two decades ago, it’s still used in aviation gasoline, or “avgas,” to prevent knocking in over 167,000 piston-engine aircrafts around the country. According to the U.S. Environmental Protection Agency (EPA), avgas is the single largest source of lead emissions in the country. Avgas released during flight has the potential to disperse lead widely in the environment, contaminating water bodies, soil near the air fields, and farms.

Lead is a well-known neurotoxicant, and children are particularly vulnerable to its devastating and irreversible impacts. The U.S. Centers for Disease Control and Prevention (CDC) says there is no safe level of blood lead in children. The EPA estimates that approximately 16 million people, including 3 million children, live or attend school within one mile of airports using leaded avgas. Researchers have found that children living close to airports with planes using avgas have higher blood lead levels than children living farther from those airports. Workers who service or refuel the aircrafts may also be exposed.

There are alternatives to avgas, and it is estimated that about 80 percent of the current piston fleet across the country could operate safely on these fuels without retrofitting. Europe already implemented policies to promote the use of unleaded alternatives. Yet, without regulatory updates in the U.S., there is little incentive for industries to change or for airports to provide alternatives.

What is the roadblock to these policy changes? To regulate lead under the Clean Air Act, the EPA must make an “endangerment finding” that documents the hazard of lead released from aviation gasoline. Despite petitions from multiple advocacy groups, however, the EPA has declined to make this determination and has insisted on the need for more data.

In the meantime, the Federal Aviation Administration (FAA) formed the Piston Aviation Fuel Initiative, a collaboration between FAA and industry to spur the development of additional avgas substitutes by 2018. Whether this effort delivers on its promise remains to be seen. And even if a replacement is “certified,” the FAA estimated that a complete phase out of leaded fuel could take 11 years.

To spur changes in the absence of efficient federal progress, action at the state and local levels is needed. For example, requiring airports to provide unleaded gasoline or adopting taxes on leaded gasoline to promote use of alternatives. Revenue generated could be used for soil lead testing or remediation at homes, schools, and parks near airports using leaded gasoline. We urge local policymakers to consider such initiatives in the coming legislative sessions.

recent report from the Pew Charitable Trusts calculated that removing lead from aviation fuel would prevent a 5.7 percent increase in child blood lead across the country and result in $262 million in gross future benefits.

Given the known hazards of lead exposure and the existence of alternative aviation fuels, we have an ethical responsibility to eliminate the use of avgas and protect our population from such a significant source of lead pollution.

How the U.S. is taking the lead to prevent lead poisoning

This piece was first published on the Interdisciplinary Association for Population Health Science (IAPHS) blog. You can see the original posting here.  

The crisis in Flint, Michigan, returned our attention to a problem that we would have preferred to believe was behind us: lead poisoning. This incident highlighted the dangers of lead-lined water pipes; but, unfortunately, there are numerous other sources of lead exposure throughout the United States. I’ve written previously about risks from contact with contaminated soil or through the workplace. Lead-based paint, outdoor air, and manufactured products also pose risks. Because of these diverse sources, eliminating lead poisoning is challenging and requires coordination across multiple programs and policies.

Understanding this complex need—and perhaps sensing the increased public concern regarding lead in the United States—the President’s Task Force on Environmental Health Risks and Safety Risks to Children recently released a report entitled “Key Federal Programs to Reduce Childhood Lead Exposures and Eliminate Associated Health Impacts.” This report describes the dozens of federal regulations and programs that have been established to address lead exposures in children. It also marks progress towards the development of an enhanced lead strategy that will address existing policy gaps.

The report is worth a read; you may be surprised by the number of existing policies and efforts aimed at mitigating lead exposure. There are almost 60 programs and activities administered by nine agencies and close to 30 specific regulations that address lead exposures, directly or indirectly, in children. Some of these programs and regulations include:

Together, all of these efforts have contributed to the impressive decline in blood lead levels in this country, as illustrated in the figure below.


Despite this progress, significant challenges remain. Exposure to lead occurs disproportionately in minority and low-income families, and future work should focus on mitigating this disparity. As prescribed by Executive Order 12898, environmental justice must be a core component of agency activities.

To meet these environmental justice goals and continue to reduce lead exposure across the country, continued funding of these programs is essential. This report demonstrates that eliminating lead hazards requires parallel efforts and synergies between nine different government agencies—from the EPA to HUD, and the Department of Education to the Department of Transportation. Therefore, in the coming years, we must ensure that these agencies continue to receive the resources to be able to adequately address this critical public health issue. Call or write your representatives to voice your thoughts on the importance of protecting funding for public health agencies.

We have come so far in addressing lead in this country; let’s make sure we can finish the job completely.

Lead exposure beyond Flint—protecting our nation’s workers

This commentary was published in the September 12, 2016 edition of Environmental Health News‘ Above the Fold. To view the original version, click here: 

By Rachel Shaffer and Steven Gilbert
Environmental Health News

Lead poisoning returned to the national consciousness this year through the tragic events in Flint, Michigan, but drinking water is only one of many exposure routes. Because of outdated federal workplace safety standards, acute and chronic occupational lead exposure occurs all too often and can harm workers and their children, who may be exposed prenatally or through lead dust carried into the home. We need to protect workers and their families by updating federal workplace lead standards based on the latest scientific research.

The U.S. Occupational Safety and Health Administration (OSHA) regulates workplace lead exposure at the national level through two standards, the general industry standard and the construction industry standard. Both of these standards are severely outdated, based on information available in the 1970s instead of the latest scientific and medical evidence.

Image adapted from CDC/NIOSH

Thus, while OSHA’s mandate is to “assure so far as possible every working man and women in the Nation safe and healthful working conditions,” these goals have not been met for workplace lead exposure.

Under the existing regulations, workers can be exposed to levels of lead that result in 60 micrograms of lead per deciliter of blood before medical removal is required, and they can return to work after their blood lead levels are as high as 40 micrograms per deciliter.

As comparison, the Centers for Disease Control (CDC) defines blood lead levels above 5 micrograms per deciliter as “elevated” and has set a “Healthy People 2020” national public health goal that aims to reduce the proportion of workers with blood lead levels above 10 micrograms per deciliter.

Exposure to levels of lead much lower than what is allowable under OSHA’s current standards have been linked to high blood pressure, decreased kidney function, reproductive effects and neurological impairments.

In industries with high potential for lead exposure, such as construction, gun ranges, and battery reclaiming/manufacturing, not only are workers at risk, but their families may also be exposed inadvertently through take-home lead dust.

Children’s developing nervous systems are particularly vulnerable, and lead exposure can result in intellectual impairment. Stricter standards that require lower workplace lead levels and better personal protection will substantially reduce the dangers associated with take-home lead exposures.

In addition, since lead released from bones during pregnancy easily crosses the placenta, children born to lead-exposed workers are at risk for neurodevelopmental and other adverse health effects. Better standards will reduce potential fetal lead exposure in female workers of childbearing age.

Both California and Washington State are in the process of updating their own occupational lead standards. But, why should workers in only two states be privileged to improved health protections? OSHA standards, which cover all workers across the country, should also be strengthened to adequately protect workers and their families.

In the interim, though, enforcement of company compliance with existing federal regulations is also critical. A recent blog post from the U.S. Department of Labor described a case in which OSHA officials responded to worker complaints and cited a Wisconsin shipyard operator with 19 willful violations of the lead standard after detecting elevated blood lead levels in 75 percent of employees tested.

OSHA regulates workplace lead exposure at the national level through two standards. Both of these standards are severely outdated.The incident illustrates the importance of maintaining a well-funded OSHA ensuring it has the resources to monitor adherence to the standards. However, a draft bill for fiscal year 2017 suggests that OSHA’s budget would be cut significantly, which may prevent these enforcement activities and thus put workers at further risk.

We have the scientific and medical evidence that documents the harms of elevated blood lead levels, and we have the technology to reduce occupational lead exposure.

Now it is time to take action to put elevated workplace lead exposure behind us by rapidly adopting a standard that is aligned with CDC’s existing public health guidance, which classifies blood lead levels above 5 micrograms per deciliter as elevated.

We must strengthen OSHA standards for lead and provide sufficient support for the agency’s enforcement actions. The health of our workers – and their children – depends on it.

Outdated lead standards put Washington workers, families at risk

This op-ed originally appeared in the August 1, 2016 print edition of the Seattle Times. See here for the online posting: 


FGGM_Pb5Image credit:

By Rachel Shaffer and Steven Gilbert

THE tragedy in Flint, Mich., thrust lead contamination into the spotlight, and much attention has been focused rightly on the terrible consequences of childhood lead exposure.

Most people, however, are unaware that adults can also experience serious health effects from lead. As with many chemicals and hazards, workers are often more highly exposed than the general population. Examples of industries with high potential for lead exposure include construction and battery manufacturing. In these and other industries, not only are workers at elevated risk, but their families may also be exposed inadvertently through take-home lead dust.

In Washington state, there are two primary standards that regulate occupational exposure to lead: the “general industry lead standard” and the “lead in construction standard.” Unfortunately, both of these standards are severely outdated, based on information available in the 1970s instead of the latest scientific and medical evidence.

Under the existing inadequate standards, workers can be exposed to levels of lead that result in blood-lead levels up to six times higher than the Centers for Disease Control and Prevention’s maximum health goal for adults.

Moreover, levels of lead much lower than Washington state’s current standard have been linked to high blood pressure, decreased kidney function, reproductive effects and neurological impairments. Standards should change to reflect the latest public-health recommendations and scientific evidence.

To adequately protect workers and their families, blood-lead levels must be routinely monitored when there is any possibility of lead exposure, and individuals should be removed from their duties when their blood-lead levels are above the National Institute of Occupational Safety and Health’s reference level for adults.

We have the technology to drastically reduce occupational lead exposure. We need to give workers the safe workplaces they deserve.

The health benefits of updated occupational lead standards would extend beyond workers and would also protect their children and families.

Workers often inadvertently carry lead dust on their skin and clothing when they return home, which can cause lead poisoning among family members. Stricter standards that require lower workplace lead levels and better personal protection would substantially reduce take-home lead exposures.

Second, since lead easily crosses the placenta during pregnancy, children born to lead-exposed workers are at risk for neurodevelopmental and other adverse health effects. Better standards would reduce potential fetal lead exposure in female workers of childbearing age.

The state Department of Labor and Industries should move swiftly to update our existing outdated lead standards. Workers in this state should not be subject to the health risks of lead exposure. Nor should their children suffer the secondhand consequences of this well-known poison.

It’s time to take action and give our workers and their families the protection they deserve.

For additional information on the Washington State process to update the occupational lead standard, please visit: