Founded by Blue Circle Industries of the United Kingdom early 1930s, East African Portland Cement Company started its trading activities by importing cement for pioneer construction work in East Africa.

The company was named Portland owing to the resemblance in colour and quality of set cement to the Portland stone that was being quarried in Dorset, England.

In February 1933, Portland was incorporated in Kenya and opened a factory in Nairobi's Industrial Area. The company had one small cement mill (Cement Mill No. 2) and imported clinker from India. The plant’s initial production capacity was 60,000 tonnes a year.

By December 1956, construction of a new factory started in Athi River. Commissioned in 1958, the factory consisted of a Rotary Kiln (WET), a big mill (Cement Mill Nos.1 & 3). The production capacity doubled to 120,000 tonnes a year.

A fast-growing economy saw a rise in business activities and national development projects, leading to a higher demand for cement.  Consequently, the company commissioned a new Rotary Kiln (WET) in October 1974, which added 180,000 tonnes to the production capacity, bringing the total capacity to 300,000 tonnes a year.

In 1979, as the cement demand grew even further, the company carried out a minor up-rating, which involved putting up a new and bigger Raw Mill (No. 4),  converting the older Raw Mill into Cement Mill No. 3.

This led to increased fan capacities for both kilns, which resulted in more clinker production. The mini up-rating increased the production capacity from 300,000 to 340,000 tonnes a year.

In October 1996, the company commissioned a new kiln, complete with Raw Mill (Vertical Roller– Atox), a bigger limestone crusher and a modern raw material pre-blending system.

This brought factory production to 600,000 tonnes a year. Today, East African Portland Cement Company has a large share of the local market, with Blue Triangle Cement being a brand of choice throughout Kenya and parts of the East African region.