| Business | Phone |
| First Environmental Labs Inc 1600 Shore Rd D, Naperville 60563 | (630) 778-1200 |
| Environmental Microbiology Lab 1979 N Mill St 102, Naperville 60563 | (630) 718-1566 |
| Radon Reduction Systems Inc Naperville 60540 | (630) 357-9474 |
| U S Biosystems Inc 200 N Washington St 200, Naperville 60540 | (630) 548-1034 |
| Midwest Radon Detection Llc Naperville 60563 | (630) 245-9009 |