but when the tires are damaged beyond repair, reynaldo stores them in his courtyard. every few days people pull up in their old trucks and collect them. they later sell them to the cement industry for around 12 cents a piece. cemex is the dominican republic's largest cement maker. every day several truckloads of old tires are delivered to its plant. their high petroleum content makes the tires a good source of fuel. >> the tires are a waste product that if you do not use, they will be left on the street, plagues will grow up and the tires will take about 1000 years to disintegrate. so, each time we use a tire, we are reducing our primary fuel consumption, meaning that it is going to be less emissions, less co2, and more environmentally friendly. >> close to 80 tires can be burned per hour in the largely enclosed incinerator, which releases only a small amount of pollutants. but, overall, the project does little to change the company's carbon footprint. the firm's main energy source is still coal, making the cement factory one of the country's largest emitters of co2.