Original: Following the introduction of fire safety legislation controlling the use of highly flammable Nitrate film stock, travelling shows were largely replaced by purpose built cinema halls, which rapidly proliferated.
Simplified: Following the introduction of fire safety rules controlling the use of highly flammable Nitrate film stock, travelling shows were largely replaced by purpose built cinema halls, which spread quickly.
Simplified: After the introduction of fire safety legislation, controlling the use of highly flammable film used for cinema, travelling shows were largely replaced by purpose built cinema halls, which rapidly increased in number.
Simplified: Following the introduction of fire safety laws controlling the use of highly flammable Nitrate film stock, travelling shows were largely replaced by purpose built cinema halls, which rapidly grew.