Image courtesy of Elkus Manfredi Architects

A 1960s office park near Route 128 would be replaced by a life science project under plans under review by Waltham officials.

Greystar is proposing its second lab project in Greater Boston after breaking ground last year on the 74M tower in Somerville.

Updated plans submitted Aug. 3 include a 5-story, 169,700-square-foot office-lab building at 379-395 Totten Pond Road.

Greystar is seeking approval of variances from the Waltham Zoning Board of Appeals, citing the difficulties of building on the western half of the site because of soil conditions. A public hearing Wednesday was continued until Aug. 29.

The property currently includes three connected office buildings completed in 1967. Real estate records list the owner as Totten Pond LLC and Waltham-based Paino Associates.

Only 38 percent of the 1.2 million square feet of lab space completed in Greater Boston since the beginning of 2023 has been leased, according to a recent report by Cushman & Wakefield. Companies leased just over 305,000 square feet of lab space during the second quarter.

Greystar entered the Greater Boston life science market with a high-profile project in 2022, breaking ground on the 465,000-square-foot 74M office-lab tower at 74 Middlesex Ave. in Somerville’s Assembly Square. Greystar is partnering with the Canada Pension Plan Investment Board on a potential $2.5-billion pipeline of life science projects in Greater Boston and other U.S. metros.