Mortality from cancer of the lung and bladder and chronic obstructive pulmonary disease are related to exposure in Söderberg smelters. The cause of increased stomach cancer mortality is unclear. Excess mortality from some other diseases may be explained by factors other than coal tar pitch volatiles exposure.

Statistically significant improvements were found in mortality from all causes combined, from cancer and from cancer of the lung and bladder. Slightly increased mortality continues from certain other causes.

The cancer incidence results are consistent with those from mortality studies, but identify other cancers that deserve scrutiny in future follow-ups.