April 20 marked the four-year anniversary of the infamous 2010 Gulf of Mexico oil spill, in which BP's (NYSE:BP) Macondo well blew out, destroying the Deepwater Horizon semi-submersible rig and causing the worst accidental oil spill in history.

In addition to the tragic loss of 11 workers onboard the rig, the accident has caused widespread environmental damage -- the extent of which is still hotly debated -- and has cost BP tens of billions of dollars in fines and penalties.

But with Gulf of Mexico drilling activity poised to grow sharply over the next several years, many wonder whether BP and other oil companies' approaches to drilling are any safer than they were four years ago. In terms of safety, has anything fundamentally changed, or are we destined to repeat history?

Progress so far
Let's start with the progress that has been made since Macondo. For one, the Minerals Management Service, the regulatory body tasked with overseeing Gulf drilling, has been split intro three new agencies that separately issue leases, collect royalities, and oversee drilling safety. This restructuring has greatly improved the safety of Gulf drilling, according to a report issued last year by the Oil Spill Commission Action, an investigative government panel set up in the aftermath of the spill.  

One of these new agencies, the Bureau of Safety and Environmental Enforcement, or BSEE, has also enforced a number of new safety regulations. Last year, it finalized a new set of rules that require new cementing integrity tests and casing/cementing plans to be independently verified by a professional engineer. BSEE also now requires Gulf operators to have a Safety and Environmental Management System outlining specific steps to limit human error.

BP's new measures
BP also says it has taken key steps to reduce the risk of another major accident. In 2011, it set up a new monitoring center in Houston that provides 24/7 real-time communications between its Gulf rigs and its onshore engineers. The company is also testing whole systems, as opposed to individual parts, to more accurately simulate real-world conditions.

It is also pushing rig equipment past rated limits to better understand how the equipment will react under extreme conditions. BP also points out that it now has a team of 36 people exclusively dedicated to improving the reliability of blowout preventers, a key piece of equipment designed to cap a well in the event of a blowout and whose failure was key in exacerbating the severity of the 2010 spill.

Threats remain
But despite this progress, major threats to deepwater drilling safety remain, according to Elizabeth Birnbaum, the former director of the Minerals Management Service. In a recent New York Times opinion piece, she specifically points to the lack of progress in improving the safety of blowout preventers.

She argues that federal regulators failed to act on the findings of a December 2011 report by the National Academy of Engineering, which highlighted numerous shortcomings with Deepwater Horizon's blowout preventer and recommended that new safety standards be implemented.

Though regulators agreed to set new standards for blowout preventers by the end of 2012, they have yet to even propose new rules much less enforce new standards. Meanwhile, drilling activity in the Gulf continues to grow with many operators still using older blowout preventers.

Conflicting challenges
Though the oil and gas industry and federal regulators appear to have made significant progress in improving the safety of offshore drilling in the four years since the Deepwater Horizon tragedy, major concerns still remain, especially with regard to the safety of blowout preventers.

Another concern is how exactly Big Oil companies will balance the conflicting challenges of improving safety measures while simultaneously cutting costs. For BP, cost cutting and a lack of corporate oversight on safety and accident prevention measures were key reasons that led to the tragic 2005 Texas City refinery explosion.

That's why I can't help but wonder if this renewed focus on cutting costs might lead Big Oil companies drilling in the Gulf of Mexico to cut corners on safety and precautionary measures, potentially inviting another major oil spill. What do you think?