Tarenni Colliery 1858, when the Primrose Colliery was owned by Morgan and Lewis, fumes of an engine boiler suffocated 14 men and boys, and 7 horses. According to HM Inspectorate of Mines and Quarries data, outside the Gwendraeth valley, Tarenni Colliery had the highest set of recorded incidents for coal damp and methane gas explosions. In total during its production lifetime, there were six outbursts in which three men lost their lives: one on 12 December 1914; two on 17 February 1941. On 1 November 1909, water from the abandoned Ynysgeinon pit caused the death of five miners at Tarenni No.2. On
Lakshmi Mittal government said it wanted to renegotiate the 2004 sale to ArcelorMittal. Employees of Mittal have accused him of "slave labour" conditions after multiple fatalities in his mines. During December 2004, twenty-three miners died in explosions in his mines in Kazakhstan caused by faulty gas detectors. In 2002 Plaid Cymru MP Adam Price obtained a letter written by Tony Blair to the Romanian Government in support of Mittal's LNM steel company, which was in the process of bidding to buy Romania's state-owned steel industry. This revelation caused controversy, because Mittal had given £125,000 to the British Labour Party the previous year.