Air leaks can really sip the heat right out of a house. Our biggest ally in the war against air leaks is caulk. This amazing compound can seal the spaces between our windows and our walls, our electrical outlets and our door frames. It's great stuff. However, there are some health concerns when it comes to caulk.
Before you seal off your thermal envelope completely, you need to have adequate ventilation in your home. Have your indoor air quality assessed before sealing off all fresh air. As Lloyd Alter has pointed out, you must be very careful when covering any exhaust port. And as Steve Thomas wrote in a blog post, it is the job of any green builder to design a home to change out the indoor air every three hours. As you can see, it is important to have some method of air exchange in the home.
The second big health concern behind caulk is the poisons that exist within it. Here is a list of those poisons. This list may not be entirely comprehensive.
From PennState Hershey:
Vulcanized butyl rubber
These poisons are most harmful if swallowed. But health problems can stem from inhalation and exposure to the eyes and skin. Symptoms include:
Loss of vision
Pain in the throat
Pain or burning in the nose, eyes, ears, lips, or tongue
Blood in the stool
Burns of the food pipe (esophagus)
Low blood pressure that develops rapidly
Breathing difficulty (from breathing in the substance)
Throat swelling (may also cause breathing difficulty)
Caulking is not something to be messed around with. Your best bet is to get a brand of caulking that doesn't produce air-quality problems, like GreenStrides for example. Then you can have your sealed thermal envelope and clean indoor air, a veritable cake-and-eat-it-too situation.