Its warning comes after a North East company was fined for removing asbestos from a building without a licence.
Regional secretary of the GMB, Tom Brennan said: "Despite strict rules governing the use and removal of asbestos it is all too common to find the material dumped in unsafe environments.
"Unscrupulous companies think they can avoid the red tape and extra costs by not applying for a licence to remove asbestos when one is needed.
"GMB members should protect themselves by ensuring their employers are disposing of asbestos correctly. They should report any incidents of the incorrect disposal of asbestos to their union health and safety representative."
His comments come after North East Environmental Ltd, based in North Tyneside was fined £4,600 at North Shields Magistrates Courts for not holding a licence for the removal of asbestos.
The company was renovating the former Pipeline Centre at Harvey Combe, Killingworth between September 25 and October 10, 2006 at the time.
The company pleaded guilty at North Shields Magistrates Court earlier this month.
Director of the company Henry Robinson, of Holmlands, Monkseaton, was also fined £4,600 after he admitted a similar offence.
The company and Mr Robinson shared payment of court costs of £4,917.20.
Head of Asbestos Policy
Ian McFall, head of asbestos policy at Thompsons Solicitors, which represents many union members affected by asbestos related diseases said people are still being exposed to asbestos decades after it was recognised as a dangerous substance.
He said: "It is shocking that despite the strict regulations which apply to asbestos removal we are still hearing about incidents like this where employers fail to comply and are exposing innocent people to the risk of inhaling the dangerous dust.
"Trade unions play a vital role in educating workers about the dangers of asbestos, in campaigning to make sure health and safety legislation is enforced and fighting for compensation for members and their families.
"Asbestos is the single biggest industrial killer. The number of asbestos-related deaths is not expected to peak until 2010 but if companies continue to flout the rules it could continue to cause deaths well into 2050 and beyond."
Asbestos disease diagnosis? Talk to us for advice and support on how to secure compensation.
If you or a loved one have been diagnosed with an asbestos-related disease, we can support you with advice on how to make a claim.
The process will be explained in plain English and with no obligation – our priority is to provide you with the best, expert advice on whether you have a valid case for compensation, and to signpost you to further sources of support.
There are strict time limits applied to making a claim – usually three years from the date of diagnosis. It doesn’t matter if the exposure to asbestos took place – as it often does – decades ago, the three year time limit applies to the date of knowledge of diagnosis or date of death.
For further information, visit our How to Make A Compensation Claim page.