Greystar has filed plans for its second life sciences development in Somerville's Assembly Square neighborhood.

The firm filed an environmental notification form with the Massachusetts Environmental Policy Act Office last week that detailed plans for 1.4M SF of lab and hotel space at 20-23 Cummings St. The proposal calls for three buildings: 1.25M SF of lab buildings across two 20-story towers and a 162K SF, 200-room hotel.

"The site will be revitalized to match the surrounding context of a growing life-science corridor and a booming mixed-use Somerville neighborhood anchored by the shops, restaurants, and residences of Assembly Row," the proposal says.

The project would also include 11K SF of retail and restaurant space, a 4K SF daycare and 738 below-grade parking spaces. The developer would demolish the 99 Restaurant and La Quinta hotel on the site, Banker & Tradesman first reported.

The first phase is planned to start with the demolition of the existing hotel and the construction of one of the lab/office buildings at 23 Cummings St. The second phase would demolish the restaurant and construct the second lab/office building at 20 Cummings St. The third phase would include the construction of the hotel, but its beginning "will be dependent on market conditions."

The proposal comes at a difficult time for Greater Boston's life sciences market, as activity continues to slow and demand has dropped, with 1.5M SF of new space delivered vacant last quarter, according to JLL.

The development would be the second life sciences project Greystar has undertaken in Somerville. The first was 74M, or 74 Middlesex Ave., a 465K SF development that broke ground last year next to the new project site.

The city has seen other big developments, including the first phase of BioMed Realty's 495K SF Assembly Innovation Square. Cabot, Cabot & Forbes is planning to acquire a Home Depot-anchored site, which the firm wants to transform into life sciences and residential space.