In order to comply with EPA (Environmental Protection Agency) regulations, and at a cost of about $5.2 million per ICBM, the rocket motors on 500 Minuteman III missiles will be replaced with new ones. These rockets will emit less toxic chemicals when used.
EPA regulations do not apply in foreign countries, so no changes are being made to reduce the harmful environmental effects of the nuclear warheads.
Disclaimer The opinions expressed herein are my own personal opinions and do not represent my employer's view in anyway.