DOVER, Del. — Dow Chemical and the DuPont Co. announced Friday that they are merging in a $130 billion chemical industry megadeal.

The merger would combine two companies that sell agricultural products to millions of farmers around the world, and make a variety of chemicals for consumer and industrial products ranging from electronics, automobiles, and household goods to building materials and safety equipment.

The all-stock merger calls for the two companies to combine as DowDuPont, then separate into three independent publicly traded companies focused on agriculture, material science and specialty products.

“Over the last decade our entire industry has experienced tectonic shifts as an evolving world presented complex challenges and opportunities,” said Dow Chairman and CEO Andrew Liveris.

Liveris will be named executive chairman of the combined company while DuPont Chairman and CEO Edward Breen will be CEO. The company will have dual headquarters in Michigan and Delaware where the two companies are currently based.

In conjunction with the proposed merger, which is subject to regulatory approval, both companies are taking separate restructuring steps.

DuPont announced a companywide restructuring plan to reduce $700 million in costs that includes employee and contractor layoffs affecting about 10 percent of the company’s workforce. It expects to record a pretax charge of about $780 million, with approximately $650 million of employee separation costs and about $130 million of asset-related charges and contract terminations.

Dow, meanwhile, said it is taking full ownership of Dow Corning, currently a 50-50 joint venture between Dow and Corning. Dow said the move, expected to close in the first half of 2016, is expected to generate more than $1 billion in additional adjusted annual earnings and will increase its product offerings in the building and construction, consumer care, and automotive markets.

The companies said the proposed merger of equals, approved unanimously by their respective directors, will result in cost synergies of about $3 billion that are projected to create approximately $30 billion of market value.

Under the terms of the deal, Dow shareholders will receive a fixed exchange ratio of one share of DowDuPont for each Dow share, and DuPont shareholders will receive a fixed exchange ratio of 1.282 shares in DowDuPont for each DuPont share. Dow and DuPont shareholders will own about 50 percent, respectively, of the combined company.

The proposed agriculture business would unite DuPont’s and Dow’s seed and crop protection businesses. The material science company would combine DuPont’s performance materials segment with Dow’s performance plastics, performance materials and chemicals, infrastructure solutions, and consumer solutions units, excluding its electronic materials business. Combined pro forma 2014 revenue for material science was about $51 billion.

The specialty products company would combine DuPont’s nutrition and health, industrial biosciences, safety and protection, and electronics and communications segments with Dow’s electronic materials business. Combined pro forma 2014 revenue for specialty products was approximately $13 billion.

The new company’s board is expected to have 16 directors, consisting of eight current DuPont directors and eight current Dow directors.