A friend of mine used to be a long-haul truck driver. At one point he even became a trainer working with new drivers.

Over dinner recently, I asked what was one key lesson that he would want to impart to any new driver. While he was thinking about it, his wife lit up and offered this advice (which I’m sure is not from the company manual): make sure your seatbelt is removed before you begin a hot swap.

In trucking, a hot swap occurs in a truck being driven by a team of two drivers when they are in a real hurry to make a delivery. When one is ready to take a break and turn the wheel over, rather than taking the time to stop, they may decide to trade places while the vehicle is moving down the highway.

Hot swapping green building techniques

While I’m sure that experienced drivers can “hot swap” quite, um, professionally, it is an inherently unsafe practice. This is underscored by the fact that you have to remove your seatbelt, in a speeding tractor-trailer, before you can even begin!

When I heard this, it felt to me a lot like a situation we face with some regularity in green building. We are racing to make our buildings safer, healthier for occupants, less-polluting, and lower carbon. But we are behind in that race. For example, we have been paying serious attention to the health effects of building materials on indoor air quality for only about 20 years. We have been inventing new chemicals that affect our indoor air quality for well over 100 years.

Unfortunately for the builder, homeowner, or renter who simply wants some reliable advice on what to worry about from an environmental perspective, and what not to worry about, things sometimes change or crop up unexpectedly. And we’re not usually completely ready with a seamless hot swap. Remember when compact fluorescent bulbs first came out? Remember the first low-flow toilets? Best forget them.

The issue of the day? SPF safety

The issue of the day is spray polyurethane foam (SPF) insulation products. Last month the U.S. Environmental Protection Agency (EPA) released a new action plan for a key family of chemicals used in SPF. Isocyanates, such as MDI (methylene diphenyl diisocyanate), are chemicals that react with polyols to form polyurethane. They can also cause skin, eye, and lung irritation, asthma, and chemical sensitization when absorbed through the skin or inhaled.

Polyurethane is in a lot of stuff, from foam mattresses to bowling balls. When it is fully reacted or “cured,” it is stable and its chemistry is not a significant concern. Some products, however, such as adhesives, coatings, and spray foam, react while being applied by builders or homeowners doing insulation retrofits, and continue to react for some hours afterwards, and may contain “uncured” isocyanates to which people may be exposed.

This is not news: worker protection protocols and quality assurance programs for SPF installation were developed by the SPF industry decades ago.

Why the fuss now?

As Steve Owens, assistant administrator for EPA’s Office of Chemical Safety and Pollution Prevention, put it, “There has been an increase in recent years in promoting the use of foams and sealants by do-it-yourself energy-conscious homeowners, and many people may now be unknowingly exposed to risks from these chemicals.” You can add to that a growing number of complaints about adverse health effects from homeowners and occupants of office buildings where SPF has been applied during energy retrofits.

EPA’s SPF action plan for MDI is being developed within its Design for the Environment (DfE) program under jurisdiction from the Toxic Substances Control Act (TSCA), which requires U.S. chemical manufacturers, importers, processors, and distributors to report to EPA any information suggesting that one of their chemicals “presents a substantial risk of injury to health or the environment.”

While the reported data is technically public information, penetrating it is very difficult, in some measure because manufacturers often claim confidentiality for proprietary components in their chemical formulations. But the cumulative evidence to date has moved EPA to take real action on this issue, mainly to gather reports of adverse health effects from manufacturers, and to consider initial rulemaking for both consumer-applied and professionally applied SPF products.

The action plan leaves open questions about how far EPA will go to clamp down on these products, but it’s safe to think of this as a shot across the bow from EPA for the SPF industry.

We don’t know much about SPF offgassing

In addition to the presence of MDI in the product, the chemical reaction and curing of SPF can produce other chemicals of concern: excess isocyanates, aldehydes, amine catalysts, and other volatile organic compounds (VOCs). We don’t know much about the nature and quantities of offgassing of these substances, the curing rates of SPF, or how health risks can change with improper environmental conditions or mixing ratios during the SPF process.

To that end, there is a new ASTM standard under development. John Sebrowski, a senior associate scientist with Bayer MaterialScience and chair of the task group working on this ASTM standard, is helping develop a standard practice to establish re-occupancy times after onsite SPF application. “We are currently getting ready to conduct research using micro-scale chambers and thermal desorption techniques to measure emissions,” he said.

Safe re-entry times

When asked what relationship the current ASTM draft standard and research might have to the existing protocol offered by Bayer MaterialScience (which recommends re-occupancy times of 12 hours and 24 hours for workers and occupants, respectively), Sebrowski responded that the protocol would be used as a starting point, but “we are also investigating other approaches to measuring the emissions.”

According to EPA, safe re-entry times put forward by manufacturers vary between 8–24 hours for one-component SPF and 23–72 hours for two-component SPF. But more research and standardized testing is clearly needed. EPA is not working alone on this issue; several other federal agencies — including the National Institute for Occupational Safety and Health, the Occupational Safety and Health Administration, and the Consumer Product Safety Commission — are part of the team. Each is concerned about protecting workers or consumers from health effects from the increasingly prevalent site-applied SPF.

Should we stop using SPF?

“I think you have to be careful when you discuss the toxicity of spray foam,” says David Price, environmental scientist in the indoor environment division of EPA’s Office of Air and Radiation. “I have not seen any information at this point that there is any hazard to occupants.” While Price supports EPA’s decision to gather data on possible post-occupancy issues with SPF, he doesn’t want the public to “find the accused guilty before you hear the case.”

Price has seen some of the anecdotal evidence as well as some of the scientific findings, and says that no cause-effect relationship has yet been found between SPF installation and post-occupancy illnesses. “It’s appropriate for EPA to look at this stuff; that’s what we do,” Price said. “But I’m very sensitive about tagging a product as ‘of concern’ or ‘may be toxic'” before the data has been gathered and reviewed.

Environmental Building News contacted several builders and foam industry professionals, and found that most were unwilling to be quoted on an issue they deemed sensitive and still-unfolding. One leading green remodeler offered this perspective: “I have stopped using SPF in any of my projects at this point. I simply can’t and won’t jeopardize my clients’ health and the reputation of my company by using building materials with the emissions profile of SPF.”

Since this news came out, comments on message boards that I have seen have tended toward defense of SPF and annoyance (that’s putting it politely) at EPA. The undercurrent seems to be: Is the whole industry going to get stained because of some untrained DIYers? Let’s hope that the general public doesn’t jump to conclusions too rapidly — that EPA gathers its data and that its process works. And let’s be real: not all SPF insulations jobs are perfect — some have even ended tragically.

Recommendations for continued use

SPF has unique advantages that can be difficult to replace. If you decide to continue using it while EPA continues its work, here are some recommendations.

Make sure that your SPF contractor installs SPF correctly, employing quality control/assurance protocols such as the following the Spray Foam Quality Control – Canadian Installation Requirements, or the ABAA Quality Assurance program.

Follow current EPA recommendations on a safe approach to installation, from the publication Quick Safety Tips for SPF Users.

If you are a homeowner or building manager or employee in a building in which SPF will be installed, follow EPA’s Steps to Control Exposure.

Also, stay tuned; the SPF industry is working on a new class of SPFs — hybrid non-isocyanate polyurethanes (HPINUs) — that may pose much less serious occupant and worker health issues than our current slate of SPF building products.

What do you think about the SPF issue? Do you use it, or not? Why? Let us know below.

Tristan Roberts is Editorial Director at BuildingGreen, Inc., in Brattleboro, Vermont, which publishes information on green building solutions.

Note: Peter Yost, residential program manager at BuildingGreen, and Paula Melton, associate editor, contributed reporting to this column.