Tens of thousands of chemicals are in commerce today.  Thousands of these end up in the products we use every day.  A number of analyses have noted how little we know about which chemicals are in our products and what the health and environmental hazards are. In fact, we seem to presume that what we don’t know can’t hurt us.  Most chemicals in commerce were grandfathered in – assumed safe until demonstrated harmful – under current chemicals legislation. When concerns have been raised about certain chemicals, scientists and regulators have traditionally asked questions such as “is it dangerous?” or more often “how dangerous is it?” Or if there might be some concern they might ask “is it safe?” or “at what levels is it safe?”  These questions tend to lend themselves to detailed scientific discussions and debate over understanding the mechanisms, exposure pathways, and precise doses that cause harm.  While this type of information is important to have, these prolonged deliberations over the exact safety of a chemical seldom reach consensus, and can ultimately result in inaction.  Given the large number of unassessed chemicals, such an approach can never be efficient or fully preventive.

The solvent trichloroethylene (TCE) provides a good case in point.  TCE is a widely used solvent in degreasing operations, adhesives, etc. It works exceptionally well, but it is also a probable human carcinogen, reproductive and neurotoxicant, and one of the most common chemicals found in hazardous waste clean-up sites.  The EPA spent more than two decades (and millions of dollars) conducting a risk assessment for TCE under its Integrated Risk Information System (IRIS) program.  TCE’s toxicity has been well known for almost half a century by the scientific community, even though we didn’t know exactly how it caused damage at the cellular level.

In contrast to the “how dangerous is it?” approach inherent in the TCE IRIS assessment , under the Massachusetts Toxics Use Reduction Act, manufacturing firms were required to ask another set of questions about TCE – “is it necessary?” and “are there safer alternatives?”  These questions forced companies to think about why they were using TCE (was it actually needed in the process?) and whether there were other approaches that could fulfill the function or “service” that TCE provides (e.g. degreasing metal parts) or if that function could be eliminated altogether in a safer and more sustainable manner.  With support from the Massachusetts Toxics Use Reduction Institute in testing alternative methods, Massachusetts manufacturers were able to reduce TCE use by 95%, saving money (due to the costs of permitting, disposal and handling).  Other chemicals, such as formaldehyde, provide similar examples in which extensive debates over “is it dangerous” could be reframed as opportunities to advance the design and application of safer chemistries.

In her wonderfully written book, Making Better Environmental Decisions:  An Alternative to Risk Assessment, Dr. Mary O’Brien notes that, “one of the most essential, and powerful steps to change is understanding that there are alternatives.”  She tells the analogy of a woman standing by the edge of the river deciding whether to cross.  Scientists give her their expert opinions that it is safe for her to cross, it is not too cold or too deep (even though she will get wet).  When she doesn’t cross the river, they ask why?  She responds, “because there is a bridge over there.” Changing the questions we ask about chemical problems (is it safe to wade across the river? vs. what are the alternatives for me to get across?) can ultimately converge interests around innovation in safer chemicals and materials.  These questions are at the heart of a proactive and solutions-oriented approach to chemicals management – what we have termed the “solutions-science agenda.”

Seeking safer alternatives is at the heart of the precautionary principle, a code that has been espoused in the mission of the USGBC. While many proponents of the precautionary principle would argue that precaution requires phase-outs or bans of problem chemicals, an “uninformed” substitution may actually lead to risk trade-offs, undermining efforts to advance safer chemistry. In the case of flame retardant chemicals, for instance, concern over polybrominated diphenyl ethers led to their substitution with equally problematic chemicals that are now building up in the environment. Solvent restrictions are another example. Concerns about toxic ambient air emissions resulted in solvent restrictions, but the replacement solvents ended up being more toxic to workers. Well-informed, established processes for chemical substitution can help prevent these misinformed substitutions and can instead guide the transition to safer chemicals and materials.

To answer the questions of “is it necessary” and “are there safer alternatives”, we need new scientific tools embedded in an approach called alternatives assessment.  Alternatives assessment has been defined as “a process for identifying and comparing potential chemical and non-chemical alternatives that could replace chemicals or technologies of concern on the basis of their hazards, performance, and economic viability.”  Alternatives assessment is a step-wise, action-oriented approach that includes both a comparison of chemical and non-chemical alternatives for a particular chemical function as well as attention to the ultimate adoption of the alternative and changes that must take place for that adoption to occur.  The goal of alternatives assessment is to support informed chemical substitution, which EPA defines as “a considered transition from a chemical of particular concern to safer chemicals or non-chemical alternatives.”

Increasingly, consumers, government agencies and leading companies are demanding substitutes for chemicals of concern, even in absence of strong evidence of harm.  Many government agencies and firms have established lists of “chemicals of concern” to provide strong signals as to chemicals that should be avoided based on their intrinsic toxicological properties.  This is a critical first step away from the current chemical-by-chemical, reactive “is it dangerous” approach.  However, if our goal is advancing the adoption of safer chemicals and products, it is critical that we marry this precautionary, preventive action, with thoughtful, yet expeditious evaluation to ensure that we don’t simply avoid problem chemicals, but instead adopt safer ones.  Alternatives assessment opens up new opportunities for product and building designers to identify, evaluate, and promote the adoption of safer alternatives to chemicals of concern.  In my next blog entry, I’ll present an overview of the basic processes underlying the concept of alternatives assessment.