Check out this quote from the book,
"They wore orange Racal space suits inside the cave. A Racal suit is a portable, positive-prasuure space suit with a battery-powered air supply. It is for use in fieldwork with extreme biohazards that are believed to be airborne. A Racal suit is also known as an orange suit because it is bright orange. It is lighter than a Chemturion, and unlike a Chemturion, it is fully portable, with a self containing breathing apparatus The main body suit (apart from the helmet and blowers) is disposable, so you can burn it after using it once or twice."