In 1966 construction started on the first nuclear power plant, OKG, within the present municipality.

In October 2020 the municipal council voted in favour of the building of Forsmark nuclear waste repository, with the final decision needing to be made by the Swedish government.

In the other fields there are symbols for shipping (the anchor), trade (the staff of Mercury) and wealth (the cornucopia).

1) A minor part of Emsfors is in Mönsterås Municipality This is a demographic table based on Oskarshamn Municipality's electoral districts in the 2022 Swedish general election sourced from SVT's election platform, in turn taken from SCB official statistics.

The Swedish Social Democratic Party has been governing the city and later the municipality since 1932, however not always forming an absolute majority[citation needed].