US union leaders have launched a large-scale strike at nine refineries after failing to agree on a new national contract with major oil companies, SIA reports citing the BBC.
It marks the first nationwide walkout since 1980 and impacts plants that together account for more than 10% of US refining capacity.
The United Steelworkers Union (USW) began the strike on Sunday, after their current contract expired and no deal was reached despite five proposals.
The USW said it "had no choice".
"This industry is the richest in the world and can afford to make the changes we offered in bargaining," USW International Vice President of Administration Tom Conway said in a statement.
"The problem is that oil companies are too greedy to make a positive change in the workplace and they continue to value production and profit over health and safety, workers and the community."
Royal Dutch Shell, the lead industry negotiator, said it "hopes to resume negotiations as early as possible".