Q. Is mercaptan toxic?
A. Mercaptan is indeed a toxic gas and flammable. At high levels, it affects the nervous system. At all times, the odorant must be appropriately handled.
Q. What makes it is a good idea to inject it into natural gas?
A. The simple answer is that mercaptan is not harmful at the levels used when odorizing natural gas. The nose can detect mercaptan at a 1.6 PPB (parts per billion), and the typical range of odorants in natural gas ranges from 0-10 ppm (parts per million). Additionally, the Occupational Safety and Health Administration (OSHA) has set the permissible exposure limit for the mercaptan at 10 PPM of air.