NASA's Office of the Chief Health and Medical Officer (OCHMO) assembled a small working group to review hydrogen sulfide (H 2 S) Spacecraft Maximum Allowable Concentration (SMAC) values.

Since the end of November, the San Diego Air Pollution Control District has measured hydrogen sulfide levels above the California safety threshold in the Nestor area more than 15 times.

A federal environmental public health agency said it will investigate the potential harm caused by exposure to hydrogen sulfide in the air near the sewage-tainted Tijuana River and issue ...