South San Francisco's Sign Hill receiving a red, white and blue makeover

As the nation celebrates 250 years, a Bay Area city has updated a monument to the region's industrial history with a fresh coat of paint.

Officials in South San Francisco said the city's iconic Sign Hill letters are receiving a special one-time red, white, and blue paint job — visible to drivers on northbound U.S. 101 and flights to San Francisco International Airport.

Work began on Tuesday.

Genentech, the biotechnology giant headquartered in South City and one of the city's major employers, funded the landmark's update as part of the company's 50th anniversary.

South San Francisco is promoted by Genentech as the "Birthplace of Biotechnology," honoring the legacy of the city, as its economy transitioned from industry to biotech after World War II.

Because Sign Hill is listed on the National Register of Historic Places, having received its historic landmark designation in 1996, the project required review by the City's Planning Commission through a careful certification process.

At a meeting in May, the Planning Commission approved the temporary work after determining that the treatment would be reversible and would not damage the 97-year-old concrete letters.

Officials said environmental effects were also taken into account in accordance with the California Environmental Quality Act (CEQA).

The city has scheduled additional America 250 events, including a July 4 parade. Details can be found on the city's website.