Wait – what’s MCS?
Glad you asked, Reader. It’s crazy how you ask a question I’m about to answer!
You might not have MCS (Multiple Chemical Sensitivity). You may not even know anyone with MCS. But I invite you to walk through this illness with me.
Even if you don’t have MCS or a compromised immune system, you’ll learn the drastic effects that wayward chemicals can wreak on your body.
I want to establish some common ground, to build some understanding. Chemical safety and air quality belong to each of us. Let MCS be a warning.
What Is Multiple Chemical Sensitivity (MCS)?
MCS Medical Definition
MCS stands for Multiple Chemical Sensitivity. It is also known as idiopathic environmental intolerance or environmental illness.
It is not a universally accepted or formally defined medical illness or diagnosis.
Some believe it is a psychological response to the chemical body burden, the consequence from thousands of little-understood chemicals floating around our houses and offices, into our lungs and through our blood (this process is called bioaccumulation).
Others suggest it is an outward manifestation of a psychiatric problem, of a mental health issue. In fact, some cases have been solved with cognitive behavioral therapy.
MCS may be a form of TILT (Toxicant-Induced Loss of Tolerance), caused by low-level, long-lasting exposure to residual toxins from pesticides, automotive combustion products, cleaning agents, etc.
It remains a subject of study, debate and research for the medical community.
MCS Symptoms
Symptoms of MCS include headache, nausea, muscle pain, congestion, rashes, fatigue, sore throat, etc.
For some sufferers, it is similar to an allergic reaction. To others, it mimics the onset of the seasonal flu virus.
MCS Environmental Causes
Exposure to low levels of environmental chemicals may trigger these reactions. Common trigger materials include perfumes, paints, glues, soaps, fuels and plastics.
Since MCS may be linked to asthma, exposure can cause difficulty breathing or sleeping. Sufferers may be forced to immediately remove themselves from the chemical source.
How About the Rest of Us?
If you don’t suffer from MCS, then count your blessings! But don’t count yourself immune.
By some estimates, we’ve released 80,000 new chemicals into the world since the end of World War II. And we still don’t fully understand how they affect our bodies or our environment!
Everyone can benefit from a cleaner, greener world.
Didn’t anyone ever tell you not to burn a Styrofoam cup? You don’t want to breathe that stuff in!
So why breathe it in slowly, one day at a time?

Turns out, that’s almost exactly what happened with the RV industry back in 2008.
Hurricane Katrina Highlights Mobile Housing Crisis
In 2008, Hurricane Katrina climbed out of the Gulf of Mexico and deluged the northern Gulf Shores. More than 1 million people were displaced, and thousands of homes were destroyed, entombed in mud, or saturated and moldy.
Thanks to FEMA, displaced homeowners were provided shelter with thousands of travel trailers, mobile homes and Park Model RVs.
The complaints started soon after. People reported severe headaches, trouble breathing, and congestion. Some went to the hospital, or even the ER.
A federal investigation ensued. And the conclusion was that significant levels of formaldehyde were at least partially to blame. In fact, nine out of 10 trailers were in excess of the legal limit for indoor residential spaces!
Formaldehyde is an airborne toxin and known carcinogen common in manufactured wood products. It became concentrated thanks to poor ventilation combined with lots of cheap particle board and foreign plywood.
FEMA recommended,
“Families who live in travel trailers and mobile homes should spend as much time outdoors in fresh air as possible. This is especially important for families with children, elderly people, or those with chronic diseases such as asthma.”
If you want to learn more about the indoor air quality of an RV, I wrote a free mini Ebook about RV indoor air quality.
I tackle topics about RV air quality certification, ventilation requirements, material safety, VOC off-gassing, and mold growth.
Please, go read it. Especially if you intend to live in your RV full-time or seasonally, or you’re using an older recreational vehicle. Living inside an RV isn’t like living inside a house. Again, you can read it here.
So, let’s come full circle back to MCS. If you’re shopping for an RV and you’re sensitive to environmental chemicals, then I have three bits of advice.
Buy a (Truly) Used RV
1
Do you know what speeds up off-gassing? Heat and time. You can crank up one, but not the other.
Off-gassing follows exponential decay. If you’re sensitive to airborne VOCs, you should purchase an RV that is at least one (preferably two) years old and HAS BEEN USED. Leaving an RV to sit in storage 12 months out of the year doesn’t do much to help.
Now, this piece of advice is a double-edged sword. If you buy old, and not just used, then you might find yourself with a box built primarily out of OSB and particleboard. And you don’t want that.
Avoid Manufactured Wood Goods and Liquid/Spray Finishes
2
Manufactured wood goods like plywood, OSB, MDF, and particle board usually contain trace amounts of formaldehyde and other chemicals.
Now, some are better than others. No-Added Formaldehyde (NAF) veneer-core plywood is generally much “cleaner” than, say, the MDF you’d find at Home Depot.
Also, avoid liquid or spray finishes, like fresh paint or wood lacquer. Liquid finishes generally contain high amounts of VOCs due to their solvents and carriers. Use low-VOC paint and opt for UV-cured factory finishes instead.
Instead, seek out inert alternatives. Common ones include:
- Aluminum
- Glass
- Ceramic
- Bare hardwood
- Linoleum (not sheet vinyl!)
Some composite materials are also acceptable. You may be able to tolerate a polypropylene-based composite like Azdel better than a fiberglass resin-based composite like FRP.
Renovate What You Can
3 You don’t need to rip apart walls to improve the air quality of your RV.
Simple steps like:
- Replacing the flooring with sheet linoleum;
- Sealing the furniture with a shellac primer;
- Finishing with a zero-VOC finish like milk paint;
- Barricading hard-to-reach places with aluminum foil;
- And installing a premium air filter
… can work wonders!
Yes, these projects take time (a lot of time). But materials are cheap. With a little elbow grease, you may be able to drastically decrease the environmental chemicals in your RV.

Should You Consider a Custom RV?
I admit it: Custom recreational vehicles are expensive. And most “custom” builders have no idea what MCS is – let alone how to build around it!
For 90% of people, purchasing a used RV and renovating what you can is a more feasible pathway.
But if you’re extremely sensitive to environmental chemicals, then a custom-built RV may be your only choice.
Personally, I recommend finding two people: A) a custom builder and B) a green/chemically safety construction consultant. The two professionals will need to work together. Asking one person to do both may actually be more expensive in the long run.
Speaking of which … this will not be cheap. Expect to pay at least 3x the cost of a comparable mass-produced RV. And that’s just to make the RV chemically safe. Adding premium features or appliances will further increase the cost.
And it will take time. The builder will need time to design, experiment, tweak and refine. The builder will need time to source specialty materials. Nothing works perfectly the first time.
If you’re able to absorb the cost, then a premium custom-built RV could be the best solution to your housing problem.
Moving Forward
Here are some helpful links about MCS and construction practices.
- An excellent blog about non-toxic Tiny House and trailer designs.
- A product of Taunton Press, GreenBuildingAdvisor.com publishes residential construction information on sustainable, energy-efficient, and healthy homes.
- Association dedicated to assisting those afflicted with chemical sensitives.
- E-commerce site selling specialty eco-friendly and chemically safe construction materials.