(Bloomberg) -- Australian construction materials group Boral Ltd.’s sale of its fly ash unit is drawing initial interest from suitors including Holcim Ltd. and Waste Management Inc., people familiar with the matter said.

Germany-based HeidelbergCement AG has also been studying a potential purchase of the North America-focused business, which could be valued at more than $1 billion, the people said, asking not to be identified discussing confidential information.

The sales process has also attracted private equity firms, the people said. Deliberations are ongoing, and there’s no certainty the companies will proceed with formal offers, according to the people.

Representatives for Boral, HeidelbergCement and Holcim declined to comment, while a spokesperson for Waste Management didn’t immediately respond to a request for comment.

Sydney-based Boral, which announced the sale of the fly ash unit in April, wants to free up capital to reduce debt and return cash to shareholders. It agreed to sell its North American building products business to Westlake Chemical Corp. for about $2.15 billion in June. The company is looking to unwind a push into the U.S. market that dates back to its 2017 acquisition of Headwaters Inc. at an enterprise value of $2.6 billion -- an investment that was later written down.

Fly ash is a residue created by the burning of pulverized coal that can be used in concrete, grouts and other structural fillers. Considered a recycled material, companies like Holcim and Waste Management see its use as key to creating a more sustainable construction industry.

A sale of the fly ash business comes amid a boom in building products deals, with transactions valued $57 billion having been announced this year, according to data compiled by Bloomberg. That’s up more than 400% on the same period in 2020, the data show.

Spectrum Brands Inc. is exploring options for its hardware and home improvement division, people familiar with the matter said earlier in July, while AEA Investors and British Columbia Investment Management Corp. this week agreed to the sale of Springs Window Fashions, a maker of custom window coverings.

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