Greater Boston’s biotech industry has spilled out all over the region, leading some to ask: How much is too much?

Life science development has mushroomed all over Greater Boston in the last few years, leading some to ask how much is too much

Cellarity, an innovative biotech company, moved into their new lab space on South Street in Somerville in November.John Tlumacki/Globe Staff

At one point, the old Suffolk Downs horse track was touted as a site for a casino. Or the second headquarters of Amazon.

But last month, politicians and business leaders gathered near the Beachmont Blue Line Station in Revere to celebrate the launch of something else entirely: a $350 million drug manufacturing facility — the first outpost of Greater Boston’s booming life sciences industry in this traditionally blue-collar neighborhood by the sea.

“Maybe the next cure, maybe the next medical breakthrough will happen in this great city,” Joe Boncore, chief executive of industry group the Massachusetts Biotechnology Council, said at the groundbreaking. “On behalf of the 1,700 members of MassBio, I just want to welcome Revere to the ecosystem.”

Lately, “the ecosystem” has been expanding at an astonishing pace.

Long clustered in Kendall Square and the Longwood Medical Area, Greater Boston’s biotech industry has spilled out all over the region in the last few years as life sciences have taken on ever-greater importance to the local economy. Driven by ballooning private investment and rapid scientific advancement — both accelerated by the research imperatives of the COVID-19 pandemic — the lab-development cluster in Greater Boston has lately dwarfed any other in the country, and just about every other sector of the region’s real estate market.

An office building at One Rogers Street in Cambridge is being converted to lab space.David L. Ryan/Globe Staff

Today, there are labs being built above the Massachusetts Turnpike, in a former WeWork building near South Station, at the former headquarters of big-name Boston companies such as John Hancock and Au Bon Pain. Even the sprawling old home of The Boston Globe in Dorchester pivoted from creative office space to labs. There are clusters in Watertown and Waltham and, more recently, Somerville. Lately the industry has spread to some comparatively unexpected locations: Malden, Beverly, Billerica.

All told, lab inventory here has more than doubled in the last decade, to over 41 million square feet, compared with 18.6 million in 2012, according to research from real estate firm CBRE. The only US market that comes close is the Bay Area in California, but even San Francisco trails Boston by nearly 10 million square feet.

There is still far more traditional office space than lab, roughly three times as much in terms of square footage, according to real estate firm Colliers. Large and expensive to build, lab buildings gobble water and power, although they typically have about half as many employees, per square foot, as an office tower.

But with demand for office space soft amid the pandemic, even owners of traditional towers are thinking about getting into the lab business.

“The commercial office building developer is saying: I don’t have a full occupancy anymore. Can I convert my building to a lab/office environment?” said David Woolson, partner with AHA Consulting Engineers in Lexington. “They’re getting sometimes three times the rent for that type of space than they are for an office space,” which often makes lab the more profitable choice even if it’s more complex and expensive to build.

Yet challenges loom.

Some developers have begun whispering that lab demand, which has risen ever higher for years, can’t stay like this forever. They say the industry has inflated land prices, making other types of property — especially residential — increasingly expensive and difficult to develop. A number of life sciences companies have laid off workers in recent months. Biotech stock prices have been on a downward slope for months. And consulting firm Ernst & Young sees mergers and acquisitions — concentrating the sector into fewer, larger firms — on the horizon.

Some say those headwinds are to be expected in an unpredictable industry, dependent on trial-and-error scientific research and regulatory approvals. And for years, that risk had kept many commercial real estate developers — on the whole, a risk-averse crowd when it comes to spending money without a guaranteed return — out of the lab business altogether. Life sciences companies often need space faster than it can be built, forcing developers to launch projects without a tenant signed — “on spec,” in industry parlance — and pre-pandemic, many developers balked at that sort of bet.

Then COVID walloped the traditional office market. Developers had to rethink their projects. One example: Boston Global Investors’ 10 World Trade in the Seaport. Originally envisioned as 585,000 square feet of office space, the project lost its financing during COVID. BGI added a few floors of lab amid the office space — and landed $600 million in financing that allowed the firm to launch construction on the 17-story building, without a tenant under agreement.

“Believe me, investing $600 million on spec in anything … is pretty rare,” said BGI CEO John Hynes III.

The current market bullishness took a long time to build. In 2008, then-governor Deval Patrick and the Legislature pumped $1 billion over 10 years into growing Massachusetts’ life-sciences industry; Governor Charlie Baker followed in 2018 with $623 million more. Boston is also routinely a leading recipient of funding from the National Institutes of Health.

Boynton Yards is a life-sciences-oriented development going up in a formerly-industrial corner of Somerville between Kendall and Union squares.John Tlumacki/Globe Staff

Lately though, far bigger money has come from the private sector: billions in venture capital financing and other investment into local life-science companies. Last year, 26 Massachusetts-based biopharma companies went public, MassBio said. There were 21 the year before.

“We used to be really excited when venture capital in Greater Boston exceeded a billion dollars,” said Bill Kane, president of the East Coast and UK markets for lab developer BioMed Realty. “Then last year, it exceeded $12 billion.”

And that has drawn big real estate money too.

Investment giant Blackstone spent $8 billion in 2016 to buy BioMed, a longtime developer in Kendall Square but based in San Diego, and then pumped $14.6 billion more into the company in 2020 to seed a wave of new projects. BioMed’s current portfolio includes large-scale office-to-lab conversions in the Seaport and South End, a major office-to-lab conversion in the works in Somerville, and a newly constructed lab in Kendall Square.

With its sophisticated building systems and specialized tenant base, lab development has traditionally been the domain of a few developers. The biggest of those — BioMed, Alexandria Real Estate Equities, and the real estate arm of MIT — have long been dominant here and carved a healthy niche. More recently they’ve been joined by lab-focused newcomers such as IQHQ, which is led by former BioMed executives and raised $2.4 billion in its first year as a company. It quickly invested in a $1 billion lab tower over the Massachusetts Turnpike at Fenway Center and has acquired three more sites in the area, including the former Hotel Buckminster, as well as lab projects in Alewife and Andover. In April, New York-based developer Tishman Speyer and life-sciences investment firm Bellco Capital closed a $3 billion lab-development fund.

Those type of huge numbers have prompted many developers who would never normally consider lab space to give it a try. Some are pursuing not only ground-up lab construction, but converting empty offices into labs, such as Oxford Properties’ plan to convert a former downtown Boston WeWork into labs or Spear Street Capital’s conversion of the former Tufts Health Plan headquarters in Watertown to 550,000 square feet of lab space.

A view of 325 Binney Street in Cambridge, the future headquarters of Moderna.David L. Ryan/Globe Staff

That has some veteran biotech developers grumbling about the increasingly crowded lab landscape.

Executives from Alexandria, for one, frequently tout their expertise and tenant roster in earnings calls to investors, hinting they can deliver on complex projects. They have deep relationships with established drugmakers, such as existing Alexandria tenant Moderna, who last year signed a lease for its new headquarters in a different building Alexandria is constructing in Kendall Square. And they stressed that just because a project is proposed as lab doesn’t mean it will ever actually get built.

“Yes, there are a number of planned or proposed projects or dirt being moved around,” said co-CEO Stephen Richardson on a recent earnings call. “But we’ll have to see if the operators — and more importantly, the capital partners behind these projects — actually commit significant capital to the projects.”

Indeed, some small- and midsize life sciences companies are reconsidering growth right now, said Bob Coughlin, managing director of brokerage JLL’s life-sciences practice who previously led MassBio.

Sophie Guo worked at Cellarity in Somerville, with the Cambridge and Boston skyline in the distance.John Tlumacki/Globe Staff

The downturn in the stock market has prompted a slump in many biotech company valuations, Coughlin said, which has triggered layoffs from those companies trying to cut costs.

“If a company needs to raise money right now, they’ve given up three-quarters of the company to do it,” Coughlin said. “So instead, they’re saying: ‘Let’s keep the science going. Let’s get lean and mean.’”

And — despite the money flooding into life sciences real estate — not every parcel needs to be lab space, Coughlin noted.

”People are going to pump the brakes and slow down,” he said. “Things were happening really fast, and it got out of hand. And now we’ve just got to get our arms around what’s going on.”