Leaders of the unions representing 75,000 building tradespeople want freezes on construction activity in Boston, Cambridge, Somerville and Watertown to be extended state-wide.

The Massachusetts Building Trades Council executive board voted unanimously to back the idea Tuesday afternoon. The unions called on Gov. Charlie Baker to declare a statewide suspension of regular construction activity starting Friday and continuing until April 30.

“The only way to protect the health and safety of our members, their families and of the general public is to keep people apart. It is impractical and, in many cases, impossible to safely work on a construction project right now given the current state of affairs,” council President Francis X. Callahan said in a statement.

Callahan said the council made an “exhaustive consultation” of public health experts, union officials, building contractors and union members.

“In the meantime, we are working around the clock with industry stakeholders and public health experts to develop best practices and new safety protocols to ensure the safest worksites possible for the emergency and essential projects that need to continue, and for all projects when it becomes feasible to return,” Callahan added.

The council issued a list of work it considers “essential” that it thinks should not be covered by any freeze:

• Emergency utility, road or building work, such as gas leaks, water leaks and sinkholes.
• New utility connections to occupied buildings.
• Mandated building or utility work.
• Work at public health facilities, healthcare facilities, shelters, including temporary shelters and other facilities that support vulnerable populations.
• Work which ensures the reliability of the transportation network.
• Work necessary to render occupied residential buildings fully habitable.

Also on Tuesday, Baker issued new guidance narrowing the list of what kinds of construction projects are considered “essential” and allowed to go forward until May 4:

• Housing construction, including work on mixed-use projects and work that supports housing construction.
• Maintenance work, including repairs to pluming, exterminations and other services necessary to maintain hospitals and other healthcare facilities.
• Public works and other infrastructure projects.