SEATTLE — Jim Andersen has a 40-year history with hashish, the concentrated cannabis sometimes referred to as the cognac of the marijuana world.

When he served in the Air Force in Southeast Asia, he said he smuggled it home in his boots. When he was in grad school in California, he made it with a centrifuge in a lab after hours.

So when Washington was on the verge of legalizing the sale of taxed pot last fall, Andersen decided to move back to his home state and turn his hobby into a full-time, legitimate paycheck – a business that would supply state-licensed, recreational marijuana stores with high-quality hash oil.

"Every major culture that has marijuana associated with it has hash associated with it as well," said Andersen, whose company, XTracted, already has two Seattle locations serving medical marijuana dispensaries. He said his business would help prevent such pot extracts from ending up on the black market.

Substance abuse experts are concerned that such increasingly popular, extremely potent and potentially dangerous pot extracts will be sold and that state regulators’ interpretation of the recreational marijuana law will allow people to buy vastly more hash than they need for personal use.

That, they fear, will increase the chances that some of it will end up in the black market out of state.

"It’s a concern not just for our kids, but for kids in neighboring states as well," said Derek Franklin, president of Washington Association for Substance Abuse and Violence Prevention.

The legal-weed law, passed by voters last fall, allows adults over 21 to possess up to an ounce of dried pot, 16 ounces of pot-infused solids such as brownies, or 72 ounces of infused liquids such as soda. When the state-licensed stores open sometime early next year, that’s how much people will be allowed to buy.

The law precluded the sale of pure hash and hash oil, but didn’t specifically address concentrated marijuana sales. That’s led to a conversation about hash’s place in the new legal-pot world.

The regulators at Washington’s Liquor Control Board, who are charged with overseeing the creation of the new legal pot industry, issued draft rules this month saying hash and hash oil can be used in "marijuana-infused products" – even if the product that’s being infused is just a drop of olive oil or glycerin, for example.

In effect, the stores can get around the ban on hash- or hash-oil sales by simply adding a minuscule amount of some other substance to what is otherwise nearly pure THC, the primary high-inducing compound in cannabis.

Hash oils can sell for $40, $60 or more per gram, depending on quality – meaning more tax revenue for the state. If such extracts are considered a "marijuana-infused product," people would be allowed to buy up to 16 ounces of oils in solid form, or 72 ounces in liquid form. Such transactions could run tens of thousands of dollars.

"When we set the 72-ounce limit, we were thinking about marijuana juice or tea, not a high-potency extract like that," said Alison Holcomb, the Seattle lawyer who primarily drafted Washington’s law."

Holcomb said it will be up to state lawmakers to adopt new ceilings on marijuana concentrate sales early next year – before the state-licensed stores open for business. The Legislature could also tweak the law to allow for sales of pure hash and hash oil – something hash makers would like to see.

They say if they have to adulterate their product with even a drop of olive oil or glycerin, customers might instead turn to medical dispensaries or the black market.

In Colorado, which also legalized recreational pot last fall, stores will be allowed to sell hash and hash oils.

"Our goal is to replace marijuana prohibition with a system in which marijuana is regulated and taxed similarly to alcohol," said Mason Tvert, who led Colorado’s legalization campaign. "Some marijuana consumers choose to use more potent forms of marijuana, just as some alcohol consumers prefer a martini or glass of scotch over a beer."

The term "hash" covers a variety of marijuana preparations, but is generally the compression or concentration of cannabis resin rich in THC.

The preparations can involve anything from the simple shaking of the resin off the plant and pressing it into bricks to the use of stainless steel, closed-loop extraction systems that cost tens of thousands of dollars, use butane or carbon dioxide as a solvent and turn out oil that is more than 90 percent THC.

Drug-abuse prevention advocates argue the proliferation of extracts has also coincided with a dramatic rise in marijuana-related emergency room visits, often for severe panic attacks. According federal figures, there was a 62 percent jump in marijuana-related emergency room visits nationally from 2004 to 2011 – from 281,000 to 455,000.

There have also been explosions as home chemists try to make hash with sometimes dangerous solvents.

Hash oils, which are already sold at medical marijuana dispensaries around the country, can be taken by medicine droppers in liquid form, or by vaporization in the solid forms known as shatter, glass, budder or wax. By means of a metal wand, users place a "dab" about the size of a grain of rice on a glowing-hot metal stem of a pipe and inhale the resulting cloud, which delivers a powerful, nearly instantaneous high.

Andersen said many users prefer it because it gives a "cleaner" high: No plant material is burned, and people know right away what the effect is – rather than waiting an hour or more for a pot-laced brownie or other edible to kick in.

"Dabbing" has become ever more popular over the past decade; a festival in Denver this weekend (7/13-14) was devoted to it. Ralph Morgan, owner of OrganaLabs in Denver, with two medical marijuana dispensaries, said hash and other concentrates now make up nearly one-third of his business.

"This is the way the industry is going," he said.