However, the UK has no WEL for diesel engine exhaust (see page 80). After years of pressure from trade unions, a 2019 amendment to the EU Carcinogens and Mutagens Directive set a new exposure limit for diesel exhaust of 0.05mg/m3 (measured as elemental carbon). The new limit had to be implemented in EU member states, by 21 February 2023 at the latest, with underground mining and tunnel construction given a later deadline of 21 February 2026.