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
United Kingdom mines and quarries regulation in 1910 total increase of 924 in the number of persons employed. Fatal accidents resulted in 1900 in 127 deaths; compared with 1899 there was an increase of To in the number of deaths, and, as Professor Le Neve Foster pointed out, this exceeded the average death-rate of underground workers at mines under the Coal Mines Acts during the previous ten years, in spite of the quarrier " having nothing to fear from explosions of gas, underground fires or inundations." He attributed the difference to a lax observance of precautions which might in time be remedied by stringent administration of the law.