MILWAUKEE — In preparation of releasing results from its first-ever testing of dangerous fumes from roasting unflavored coffee, the U.S. Centers for Disease Control and Prevention is highlighting ways coffee companies and workers can protect themselves from potentially deadly lung disease.

The agency’s newly designed Web page warns coffee roasters that merely opening a hopper or bin of stored beans — including those that are unflavored — can expose workers to a blast of chemical compounds at levels far higher than those known to permanently destroy the lungs.

The information is aimed at corner cafes that do small-batch roasting as well as larger processing facilities that roast tens of thousands of pounds of coffee a day.

The chemicals, diacetyl and 2,3-pentanedione, are formed naturally in the roasting process and released in greater concentrations through grinding. The compounds — lauded for their buttery flavor — are also made synthetically and have been added to microwave popcorn, baked goods, candies and other products over the years to enhance the taste. The added flavoring was tied to hundreds of injuries and at least a handful of deaths in food workers over the last 15 years.

Food manufacturers began phasing out the use of synthetic diacetyl in the late 2000s amid mounting lawsuits with hefty settlements and juries awarding multimillion dollar sums.

But coffee manufacturers continued to use the chemicals to make hazelnut and other flavored coffees. In 2012, a pulmonologist in Texas spotted five cases of severe diacetyl-related lung disease in workers at a coffee roasting plant in Tyler. One was put on the waiting list for a lung transplant.

An investigation by the Milwaukee Journal Sentinel first exposed how diacetyl and 2,3-pentanedione from unflavored coffee also jeopardizes workers’ health. The newspaper hired an industrial hygienist to test the air in two roasting facilities that agreed to the sampling. Results found levels that exceeded the recommended safety limits in some cases by nearly four times the limit.

One of the companies that agreed to the testing was Madison-based Just Coffee Cooperative. Founders of Just Coffee wanted more information and requested a full health hazard evaluation from the National Institute for Occupational Safety and Health, a research arm of the CDC.

A team from the institute visited the facility last summer. Findings from their study are due out in the coming weeks. It’s the first time the agency has conducted such an evaluation at a coffee processing plant that does not use added flavors. The agency is now involved in another 10 or so evaluations in coffee plants across the country.

The national institute posted a preliminary notice to coffee workers in September, following the Journal Sentinel’s investigation.

The newest Web page, updated last week, includes specific steps companies and workers can take including administrative and engineering controls and medical surveillance, for example. It points out the importance of local exhaust where tasks such as grinding and packaging take place and how proper ventilation is critical. It also advises enclosing the processes whenever possible and notes the requirement to inform workers of the dangers they face. And it encourages workers to report symptoms such as shortness of breath and chronic cough.

The Journal Sentinel also identified five workers from multiple coffee shops with symptoms and lung function tests that doctors familiar with diacetyl-related disease deemed red flags that warranted further examination.